Indonesia Conference Directory

Corresponding Author
Teruyuki Toba

Institutions
1 Department of Advanced Materials Science, Graduate School of Engineering, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0301, Japan

2 Department of Chemistry, Faculty of Science, Okayama University of Science, , 1-1 Ridaicho, Kita-ku, Okayama 700-0005, Japan

Abstract
We introduce SuperAtom, which is called a modern alchemy and has been studied around the world. The SuperAtom is a nanocluster composed of multiple atoms, for example Al13. But very interestingly, the “SuperAtom” can mimic the chemical properties of “atom”, for example, the Al13 exhibits the halogen atom Cl. If this SuperAtom is constructed to an appropriate size and can be synthesized freely, there is the possibility to be placed as an "artificial atom" in a three-dimensional periodic table such as the conventional two-dimensional periodic table. In recent years, the exhaustion of rare metals has become a big problem, so that in the next generation of materials and devices, the SuperAtoms play as an important role, and it is expected to be used for various materials or as a substitute for expensive metal catalysts such as Pt. From these points of view, the SuperAtoms have been studied all over the world up to now, but there is not much studies on their electronic structures. Therefore, in this study, we have analyzed the electronic state of the chalcogen-inclusive type SuperAtom M@Al12 (M = Be, Mg, Ca, Sr) by means of DV-Xα molecular orbital calculation. Our analysis revealed that the electronic configuration of the SuperAtom, which changed only the central atom, depends largely on the kind of doped atom. And we can also confirm the “SuperAtomic hybrid orbital” composed of SuperAtomic orbitals, and chalcogen characteristics.

Keywords
SuperAtom, SuperAtomic Hibrid Orbital

Topic
DV-Xa Method

Link: https://ifory.id/abstract/U8T6JGYCWK3w

Corresponding Author
Takeyoshi Oguma

Institutions
a. Department of Advanced Materials Science, Faculty of Engineering, Kagawa University
2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0369 JAPAN

b. Department of Chemistry, Faculty of Science, Okayama University Science

c. Department of Chemistry, School of Science and Technology, Kwansei Gakuin University

Abstract
Metal complexes exhibit significant physical properties such as electrical conductivity, magnetism and optical properties. They can be controlled by changing the ligand field splitting of the d-orbital of the central metal ion. We have investigated the reversible spin crossover phenomenon by changing the ligand field splitting in six-coordinated metal complexes ML6. In this study, we focused on the change of the spin states by JahnTeller distortion in the case of an octahedral hexa-coordinated metal complexes ML6, involving 2 types of different ligand molecules. In addition, we have used DV-Xα and DVME methods in order to calculate the electronic state. In order to reproduce the effect of the JahnTeller distortion in the calculation, a uniaxial anisotropic distortion has been applied into the octahedral hexa-coordinate metal complex. The purpose of this research is to study the mechanism and phenomenon of the spin state changing by studying the spin crossover phenomenon.

Keywords
Complex

Topic
DV-Xa Method

Link: https://ifory.id/abstract/ZPvbBCL4xenD

Corresponding Author
Alexander Ogurtsov

Institutions
National Technical University “KhPI”, Kyrpychova Str. 2, Kharkov 61002, Ukraine

Abstract
The exciton-photon interaction leads to the formation of polaritonic states energetically positioned at both sides of the initial exciton. In a large ideal crystal of cubic symmetry, where the interval of the longitudinal-transverse splitting does not contain excitonic levels, the polaritonic dispersion branches lie beyond this interval at both sides of its boundaries. On the contrary, in a crystalline grain comparable or less in size than the wavelength in the substance, the interval of the longitudinal-transverse splitting is filled in continuously by excitonic states intercepting a significant part of the oscillator strength of the excitonic transition. The photoluminescence spectra of atomic cryocrystals (solid Xe and Kr) were measured at the Superlumi experimental station at HASYLAB, DESY, Hamburg. Unlike previous works, where the red polaritonic shift was small commensurably with a weak inelastic polariton-photon scattering, a large polaritonic shift of luminescence is not due to energy dissipation, the energy conservation law being met due to equal probabilities for opposite-sign energy shifts. Such effect is possible if the crystalline grains are comparable in size with light wavelength, which provides the filling in the interval of the longitudinal-transverse splitting by excitons with sufficient oscillator strength. And the sample structure must be perfect enough to lowering the exciton scattering rate with respect to the rate of the polariton formation through exciton-photon coupling. For the first time the excitation spectra of free-exciton luminescence band were recorded simultaneously below the bottom of excitonic band E and within the interval of the longitudinal-transverse splitting. The luminescence of non-equilibrium polaritons was observed both within the longitudinal-transverse splitting interval and at photoexcitation below E. The excitation spectrum below the bottom of excitonic band is determined by competition of two processes. The first one is the creation of excitons by photons with energy E at the Lorenz tail of excitonic absorption. The second process is a competing absorption related to the direct formation of two-site excitonic polarons (self-trapped excitons). Both excitation spectra of polaritonic luminescence below E and within the longitudinal-transverse splitting interval show high sensitivity to crystal quality of the samples.

Keywords
exciton-photon interaction, longitudinal-transverse splitting, inelastic polariton-photon scattering

Topic
DV-Xa Method

Link: https://ifory.id/abstract/R94qHUJam2hw

Corresponding Author
Yoshiki Fujikawa

Institutions
Department of Advanced Materials Science,
Graduate School of Engineering,
Kagawa University

Abstract
Metal complex indicates the significant physical properties such as magnetism, electrical conductivity and an optical property due to the electronic interaction between the ligand molecule and the central metal ion. We have evaluated the magnetism of the metal complex by controlling the ligand field splitting, which is the energy splitting of the d-orbitals. The magnetic phenomenon of such compounds are realized as a result of the electronic state based on the transition metal coordination complexes, and which can be switched between high spin (HS) and low spin (LS), that is called a spin-crossover (SCO) phenomenon. Our group have been investigated the way how to control the spin state according to the concept of a distortion. The five-coordinated metal complex ML5 has been experimentally confirmed to be a molecular distortion called the Berry pseudorotation (BPR). In the BPR process, both the axial and equatorial ligands can move at the same rate of increasing the angle between the other axial or equatorial ligands in five-coordinated metal complex. The classical BPR mechanism changes its molecular symmetry between two independent trigonal bipyramidals (TBPs) of D3h symmetry via a square pyramidal (SP) of C4v symmetry. The distortion parameters 5 are proposed in order to represent the distortion of the BPR process quantitatively. In this work, we predicted the possibility of the SCO phenomenon in intramolecular exchange mechanism through the BPR process in a five-coordinated metal complexes. 　

Keywords
Spin-crossover, Berry pseudorotation, Five-cooridnated Metal complexes

Topic
DV-Xa Method

Link: https://ifory.id/abstract/jQVuDGtFEhe6

Corresponding Author
Takaki Nishimura

Institutions
1 Master course student, 1,2 Department of Advanced Materials Science, Graduate School of Engineering, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa 761-0301, Japan,
E-mail : s18g576[at]stu.kagawa-９u.ac.jp, Tell : +81-87-864-2414

3 Faculty of Engineering, Niigata University, 8050 Ikarashi 2 nocho, Nishi-ku, Niigata, 950-2181, Japan

4 Department of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama 700-0005, Japan

Abstract
Considering our lives, novel energy production is so required, and many scientists have been investigated this problem from a lot of views. One of the ways for the new energy productions is the solar power thermochemical production by an oxidation-reduction reaction of the ceramics CeO₂ (ceria). In this research, the ceria is used for obtaining an H₂ gas in vapor reaction in high-temperature thermal equipment which has a heat production system consisting by focused sun light. Nowadays technology has been also developed to keep a human living, not to harm the Earth environment. From these points, it is realized that how the H₂ gas is important for our lives, so we are trying to improve the thermochemical H₂ gas production by means of a ceria as a catalyst. Our purpose in this study is, to point out what effects occur in doped ceria-s thermal reduction (TR) reaction by using DV-Xα method. Comparing the models between the pure ceria and the Mn doped ceria, we have realized the difference by the reaction. In this appearance, one of the considerations is a view from p-DOSs (partial-Density of States), in which there are different O-2p DOSs by different crystal structures. From this view, we considered that the ceria structure would become more stable and more flexible to cut the Ce-O bonding to keep the stable cyclic thermal reaction in Mn doped ceria.

Keywords
Ceria, H₂ gas, Thermal reduction (TR) , Mn doped ceria

Topic
DV-Xa Method

Link: https://ifory.id/abstract/zyGu7n8MtBjf

Corresponding Author
Yoshiyuki Kowada

Institutions
a) Hyogo University of Teacher Education
942-1 Shimokume, Kato-shi, Hyogo 673-14, JAPAN
* ykowada[at]hyogo-u.ac.jp
b) Department of Applied Chemistry, Osaka Prefecture University
Gakuen-cho 1-1, Nakaku, Sakai 599-8531, JAPAN

Abstract
All-solid-state batteries are expected as the next generation secondary batteries for their higher energy density, in-flammable properties, and so on. In order to develop these batteries, there are several problems to improve. One of them is the lower ionic conductivities of the solid-state electrolyte. In order to improve the ionic conductivity, electronic states of the sulfide-based alkali-ion conducting solid-state electrolyte were calculated by the DV-Xα cluster method. The cluster models were constructed by the coordination number reported by experimental methods and the bond length estimated from the ionic radii of each ion. The movement of the Li ion was simulated by several model clusters with different positions of the moving ion. The relationship between ionic conductivity and the differential total bond overlap population (DBOP) of the moving ion was discussed for the sulfide-based solid-state electrolytes in the several different systems. In any cases, the smaller change of DBOP of the moving cations played an important role for the fast ion movement in the solid-state electrolytes. This bonding state of the moving cations is one of the characteristics of the electronic state in the sulfide-based solid-state electrolytes.

Keywords
all-solid-state battery, solid-state electrolyte, bonding state analysis, DV-Xα method

Topic
DV-Xa Method

Link: https://ifory.id/abstract/HBXYje3qzkW6

Corresponding Author
Benjamin Walker

Institutions
University of Missouri - Kansas City

Abstract
Computation of highly-localized multiplet energy levels of transition metal dopants is essential to the design of materials such as laser host crystals. A purely first-principles density functional theory-configuration interaction (DFT-CI) hybrid computational method has been developed to accurately compute multiplet energy levels for single atoms of carbon, nitrogen, oxygen, sodium, aluminum, silicon, titanium, and chromium. The multiplet energy levels have been computed with close experimental agreement in terms of magnitude and degeneracy, and the method does not depend on empirical information (i.e. Racah parameters). The computed multiplet energy level results are distributed according to term symbols, which are then compared to experimentally-observed multiplet energy levels. The hybrid method consists of analytic computation of two-electron integrals via the DFT-based orthogonalized linear combination of atomic orbitals (OLCAO) method, which are subsequently used as input for the CI-based discrete variational multi-electron (DVME) method to obtain the multiplet energy values.

Keywords
exchange-correlation; elecron repulsion integral; multiplet; DVME; OLCAO; density functional theory; configuration interaction

Topic
DV-Xa Method

Link: https://ifory.id/abstract/XJfKkQVz7WAE

Corresponding Author
Takuhiro Yamamoto

Institutions
Department of Advanced Materials Science,
Graduate School of Engineering
Kagawa University

Abstract
The physical properties of metal complexes that are present in many places are due to the ligand field splitting of the d-orbital of the central metal ion, and the series representing the relationship of the ligand field splitting is called a spectrochemical series. This spectrochemical series represents the relationship of the ligand field splitting in the octahedral hexa-coordination structure, but no equivalent index has been shown in the tetrahedral four-coordination complex. In this study, we have investigated the creation of a novel spectrochemical series in tetrahedral four-coordinated metal complexes. As a result, it is possible to accurately understand the ligand field splitting of the tetrahedral four-coordinated metal complex, and to more effectively apply the energy for obtaining a spin crossover phenomenon in which the magnetic spin state reversibly changes. As a research flow, first, a tetrahedral structural model is created, and then the ligand field splitting is calculated using the DV-Xa method to create a spectrochemical series. As a result, we succeeded in creating a spectrochemical series of tetrahedral metal complexes. It has been found that the spectrochemical series of tetrahedral four-coordination complexes tend to hold as they are in octahedral hexa-coordination complexes to some extent, but there are cases where the series does not hold according to the peculiarity in the case of the four-coordinated metal complex.

Keywords
Spectrochemical Series, Four Coordination Complex

Topic
DV-Xa Method

Link: https://ifory.id/abstract/3m7w2c9UMHyQ

Corresponding Author
Rika SEKINE

Institutions
Department of Chemistry, Faculty of Science, Shizuoka University
836 Ohya, Shizuoka, 422-8529, Japan

Abstract
Structure and stability of the gold cluster ions of which skeleton are synthesized as a complex was analyzed using the Hückel method based on graph theory. Hückel Energy (HE) and Topological Resonance Energy (TRE) were determined for neutral, positive ion, and negative ion clusters, where all the isomers of the gold cluster up to octamer were considered. Since some graphically designed isomers include bonds that can not be realized in three-dimensional space, the screening was carried out by a molecular force field calculation with LAMMPS (lammps.sandia.gov/.). Among the isomers thus obtained, both HE and TRE were most stable when the tetramer was Au_4^{2+} with a tetrahedral structure, and with the hexamer, Au_6^{2+} with two tetrahedrons sharing one side. The complexes with these structures have actually been synthesized. On the other hand, there is no reported synthetic example of the most stable cluster of octamer Au8 with TRE and HE.

Keywords
Graph Theory, Hückel method, Gold Cluster

Topic
DV-Xa Method

Link: https://ifory.id/abstract/43NxJGtwh9rm

Corresponding Author
Mega Novita

Institutions
a) Faculty of Engineering and Informatics, Universitas PGRI Semarang, Jl. Sidodadi-Timur No.24 Semarang, Central Java 50232, Indonesia
*novita[at]upgris.ac.id
b) Lembaga Penelitian dan Pengabdian Kepada Masyarakat, Universitas PGRI Semarang, Jl. Lontar No.1 Semarang, Central Java 50232, Indonesia
c) School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen Sanda, Hyogo 669-1337 Japan

Abstract
Up to recently, it has been difficult to calculate the multiplet energies of compounds using one-electron approach. Since it only considers one electron and one nuclei, the interaction among the electrons are neglected. Previously we have successfully estimated the 2E and 4T2 levels of ruby at 0 pressure using one-electron approach based on Ohnisi-s method. We also compare the result with those calculated by many-electron approach. The one-electron approach carried out in this work is a first-principles Discrete Variational-Xα (DV-Xα) calculation. In this work, we want to perform similar study not only at 0 pressure but up to 110 GPa. We estimated the lattice relaxation effect due to the Cr3+ substitution and due to the applied pressure by using two different methods i.e., Shannon-s crystal radii and geometry optimizations. Two different types of model cluster consisting of 7 and 63 atoms will be used. The 4T2 level is simply estimated by the crystal field splitting (10Dq). Whereas the 2E level is estimated by the barycenter of t2g3 configuration.

Keywords
pressure, first-principles, CASTEP, a-Al2O3

Topic
DV-Xa Method

Link: https://ifory.id/abstract/uYLHZTGXadkB

Corresponding Author
Shuuichi Katumoto

Institutions
¹Department of Advanced Materials Science, Faculty of Engineering, Kagawa University,
²Department of Chemistry, Faculty of Science, Okayama University of Science
E-mail : s19g558[at]stu.kagawa-u.ac.jp

Abstract
Because of the chiral nature of the building blocks of living matter, an optical phenomena associated with the chirality constitute an important topic in physical chemistry. The specific optical rotation, which is a parameter for the characterization of the natural optical activity, depends strongly on the conformation of the molecule. In this study, we investigated the dependence of the optical rotation on a molecular conformation in the gas phase by calculating the electronic states of seven kind of chiral amino acids using the DV-Xα method. As a result, we can confirm the existence of an antibonding orbital on the side chain and the optical rotations are strongly related.

Keywords
Chiral Optical Rotation

Topic
DV-Xa Method

Link: https://ifory.id/abstract/uDrbRzMEgtpV

Corresponding Author
Masahiro Mikuriya

Institutions
Kwansei Gakuin University and Shimane University

Abstract
Organic chelate ligands are useful to develop metal-organic systems. Especially N,N,S-tridentate thiolic ligands have a great affinity for many kinds of metal ions to form various metal complexes from mononuclear to polynuclear species. On the other hand, the corresponding N,N,O-tridentate alcholic ligands form dinuclear CuII species exclusively. We focused on these systems in the hope of obtaining new feature of metal thiolates, elucidating interesting crystal structures and spectral properties, although most thiolato complexes are diamagnetic. We obtained mononuclear and trinuclear CoIII species with 2-[(3-aminopropyl)amino]ethanethiol. The CoIII species reacted with oxygen to form the corresponding sulfinato CoIII species. Their conversion was monitored by UV-vis spectra and DFT calculations were performed for the thiolate and sulfinato complexes. We also obtained molybdenum complexes. We will discuss these features based on the crystal structures.

Keywords
metal complexes, thiolic ligand, cobalt complexes, molybdenum complexes

Topic
DV-Xa Method

Link: https://ifory.id/abstract/4C9vF7GVQPfe

Corresponding Author
Mikhail G. Brik

Institutions
1. College of Sciences, Chongqing University of Posts and Telecommunications, Chongqing 400065, People-s Republic of China
2. Institute of Physics, University of Tartu, W. Ostwald Str. 1, Tartu 50411, Estonia
3. Institute of Physics, Jan Długosz University, Armii Krajowej 13/15, PL-42200 Częstochowa, Poland

Abstract
First-principles methods of calculations of electronic and optical properties of impurity ions in solids allow for a quantitative treatment of microscopic crystal field effects. In other words, they give a possibility of calculating the impurity ions energy levels for different geometric configurations of impurity centers, including changing chemical bond lengths and angles between those chemical bonds. From these calculations, it is possible to extract the distance dependence of the crystal field strength 10Dq, estimate the electron-vibrational interaction constants, Jahn-Teller stabilization energy, Huang-Rhys factors, Stokes shift between the absorption and emission spectra. The obtained results can be used not only for explanation of the already existing experimental results, but for the prediction of optical properties of new materials. In this presentation several examples of such calculations will be given in detail [1-6] along with discussion of practical importance of the obtained results and their potential predictive power. References: [1] M.G. Brik, K. Ogasawara, Phys. Rev. B 74 (2006) 045105. [2] M.G. Brik, J. Phys. Chem. Solids 68 (2007) 1341. [3] M.G. Brik, N.M. Avram, J. Phys.: Condens. Matter 21 (2009) 155502. [4] M.G. Brik, N.M. Avram, C.-G. Ma, Comput. Mater. Sci. 50 (2011) 2482. [5] M.G. Brik, C.N. Avram, J. Lumin. 131 (2011) 2642. [6] M.G. Brik, Physica B 532 (2018) 178.

Keywords
first-principles calculations; crystal field splitting; transition metal ions; Stokes shift

Topic
DV-Xa Method

Link: https://ifory.id/abstract/PAnwGxMRKzBX

Corresponding Author
Mega Novita

Institutions
a) Faculty of Engineering and Informatics, Universitas PGRI Semarang, Jl. Sidodadi-Timur No.24 Semarang, Central Java 50232, Indonesia
*novita[at]upgris.ac.id
b) Faculty of Mathematics, Natural Science and Information Technology Eduation, Universitas PGRI Semarang, Jl. Sidodadi-Timur No.24 Semarang, Central Java 50232, Indonesia
c) Lembaga Penelitian dan Pengabdian Kepada Masyarakat, Universitas PGRI Semarang, Jl. Lontar No.1 Semarang, Central Java 50232, Indonesia
d) School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen Sanda, Hyogo 669-1337 Japan

Abstract
In this work we estimated the optical properties of α-Al2O3: Co3+. We constructed model clusters consisting of 7 and 63 atoms. The lattice relaxation effects due to the Co3+ substitution were calculated using Shannon-s crystal radii method and geometry optimizations in the Cambridge Serial Total Energy Package (CASTEP) method. The one-electron Discrete Variational-Xα (DV-Xα) method was used to estimate the molecular orbital energies, while the many-electron Discrete Variational Multielectron (DVME) method was used to estimate the d-d absorption spectra.

Keywords
Co3+, a-Al2O3, first-principles, DV-Xa, DVME

Topic
DV-Xa Method

Link: https://ifory.id/abstract/N2HncRKrGewB

Corresponding Author
Judo Fusamoto

Institutions
Department of Chemistry, Kwansei Gakuin University

Abstract
The prediction of multiplet energies of dn ions such as transition metal ions in crystals is important for the development of novel optical materials. The first-principles calculations of the multiplet energies can be performed by the discrete variational multi-electron (DVME) method which is based on the configuration-interaction (CI) approach. Although the mutiplet energies calculated by CI calculations are generally overestimated, the overestimation can be corrected by considering the configuration-dependent correction (CDC) and the correlation correction (CC). For example, the experimental multiplet energies of V3+ and Cr3+ in α-Al2O3 were well reproduced by first-principles calculations considering CDC-CC. However, for d5 and d6 ions, the conditions of CDC-CC such as the considered transition processes have not been established. In this study, in order to optimize the conditions of CDC-CC, we performed first-principles calculations of the multiplet energies of Fe3+ and Co3+ in α-Al2O3 considering CDC-CC based on various transition processes. As a result, we could optimize the conditions of CDC-CC for Fe3+ and Co3+ in α-Al2O3 and successfully reproduced the experimental multiplet energies. By consideration of CDC-CC, the repulsion between electrons was suppressed and the overestimation of the multiplet splittings was reduced.

Keywords
First-principles calculation, Multiplet, Transition metal

Topic
DV-Xa Method

Link: https://ifory.id/abstract/RmBQhgnLExrJ

Corresponding Author
Hayato Obata

Institutions
Department of Chemisry,Kwansei Gakuin University

Abstract
The 4f2-4f15d1 transition energies of Pr3+ in fluorides are utilized for various optical materials such as solid-state lasers, phosphors, and scintillators. Therefore, it is important to predict such energies of unknown materials for theoretical design of novel optical materials. In this study, we tried to predict the 4f2-4f15d1 transition energies of Pr3+ in fluorides based on first-principles calculations and machine learning. The first-principles calculations were performed based on the relativistic discrete variational multi-electron (DVME) method using the model clusters composed of the central Pr3+ and the anions closer than the nearest cation. Although the calculated 4f2-4f15d1 transition energies of Pr3+ in fluorides showed a relatively good correlation with the experimental ones, the theoretical values tend to be overestimated by ca. 2 eV. In order to improve the accuracy of the prediction, we used the calculated transition energies as an attribute for machine learning. As a result, the regression formula to predict the 4f2-4f15d1 transition energy of Pr3+ in fluorides has been derived by machine learning using the theoretical 4f2-4f15d1 transition energy as well as some other electronic and structural parameters as the attributes. The accuracy of the prediction was significantly improved compared to the simple first-principles calculations.

Keywords
The 4f2-4f15d1 transition energies of Pr3+ in fluorides,machine learning

Topic
DV-Xa Method

Link: https://ifory.id/abstract/4xfrMNQKkvTj

Corresponding Author
Hiroyuki Hori

Institutions
Department of Chemistry, Kwansei Gakuin University

Abstract
Eu2+ ions are utilized as luminescent ions in solid-state lasers and phosphors. Therefore, the prediction of the 4f7→4f65d1 transition energy of Eu2+ in crystals is important to develop novel luminescent materials. In this work, we tried to predict the 4f7→4f65d1 transition energy of Eu2+ in oxides using first-principles calculations and machine learning. The first-principles calculations were performed based on the discrete variational multi-electron (DVME) method using small clusters composed of Eu2+ and all anions closer than the closest cation. Although the calculated 4f7→4f65d1 transition energies and the experimental ones showed some correlation, the theoretical values tend to be larger than the experimental ones by ca. 1.5 eV. Since machine learning enables one to create a predictive model of an output based on attributes, we tried to create a predictive model of the 4f7→4f65d1 transition energy of Eu2+ in oxides by machine learning using the calculated 4f7→4f65d1 transition energies and other electronic and structural parameters as the attributes. The obtained predictive model significantly improved the correlation between the predicted 4f7→4f65d1 transition energies and the experimental ones.

Keywords
Machine larning, Multiplet, 4f-5d transition

Topic
DV-Xa Method

Link: https://ifory.id/abstract/MFRHWzhwTrBG

Corresponding Author
Tsubasa Hori

Institutions
Kwansei Gakuin University

Abstract
Transition-metal ions with d3 electronic configuration such as Cr3+ and Mn4+ are utilized as emission centers in various luminescent materials such as ruby (Cr3+-doped -Al2O3) or alexandrite (Cr3+-doped chrysoberyl). Since it is difficult to investigate the multiplet energy levels of Cr3+ in a wide variety of oxide crystals experimentally, the theoretical prediction of the energy of the emission level (2Eg) is indispensable for the efficient development of novel Cr3+-doped luminescent materials. In this study, we predicted the multiplet energy of the emission level (2Eg) of Cr3+ in oxides by first-principles calculations based on the discrete variational multi-electron (DVME) method using relatively small clusters consisting of seven atoms. However, the correlation coefficient between the calculated 2Eg energy and the experimental ones was relatively low (0.52). In order to improve the accuracy of the prediction, we also performed a machine learning modeling. By using the calculated 2Eg energy and the other electronic and structural parameters as the attributes, we created the predictive model of the 2Eg energy of Cr3+ in oxides. The predicted 2Eg energies are in good agreement with the experimental ones, showing a high correlation coefficient of 0.92.

Keywords
Cr, DV-Xa

Topic
DV-Xa Method

Link: https://ifory.id/abstract/7zGfkQcdYBpg

Corresponding Author
Kazuyoshi Ogasawara

Institutions
Department of Chemistry, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, JAPAN

Abstract
The discrete variational multi-electron (DVME) program is a first-principles many-electron calculation program especially designed to calculate multiplet states of transition-metal ions and rare-earth ions in crystals. It is a configuration interaction calculation program based on the discrete-variational Xa cluster method. It has been applied to analyze various optical materials such as ruby, alexandrite, Mn4+-doped fluorides and RE-doped YLF. The variety of multiplet spectra such as d-d, f-f, f-d spectra, and X-ray absorption near-edge structures have been reproduced without any empirical parameters and the origins of the peaks in the spectra have been clarified based on the configuration analysis of the many-electron wave functions. The DVME method have been also utilized to create various energy-structure maps for Mn4+ and Ce3+ in oxides which can be used for theoretical design of novel red phosphor materials for white LEDs. Since systematic first-principles calculations are quite time consuming, we have also begun to create simple predictive models based on machine learning by using the results of the first-principles calculations as the training data. This could accelerate the creation of detailed energy-structure maps. In this presentation, I will show some of the recent applications and future perspective of the DVME method

Keywords
First-principles calculation, multiplet, phosphor, machine learning

Topic
DV-Xa Method

Link: https://ifory.id/abstract/uBbeGEmnMkWj

Corresponding Author
Norito Taniguchi

Institutions
(1)Department of Advanced Materials Science, Faculty of Engineering. Kagawa University
(2)Department of Chemistry, Faculty of Science, Okayama University of Science

Abstract
Rare sugar is a monosaccharide that there are trace amounts in nature, natural sugars present in large amounts in nature is referred to as a natural monosaccharide. Recently, the isomerase called D-tagatose-3-epimerase (DTE) was discovered, and it has a possibility to synthesize quantity of the rare sugar from a natural sugar through the enzymatic reaction. And all of hexoses can be synthesized by four kinds of enzymatic reactions (oxidoreductase reaction, aldose isomerase reaction, aldose reductase reaction and DTE reaction). In this study, single-crystal X-ray structure analysis of a sugar alcohol and its derivative have been performed in order to determine the absolute coordinates of these sugar molecules. We give an electronic state calculation by means of the DV-Xα method using the obtained data of the absolute coordinates. We also consider that mechanism of the enzymatic reaction and intermolecular energy properly such as a hydrogen bond in order to synthesize the supramolecular rare sugars (SRSs) which can be controlled their structures and the hydrogen bonds.

Keywords
supramolecule rare sugar, hydrogen bond, D-tagatose-3-epimerase

Topic
DV-Xa Method

Link: https://ifory.id/abstract/8LMmpgJVcRDF

Corresponding Author
Bui Quoc Huy

Institutions
Department of Advanced Materials Science, Faculty of Engineering, Kagawa University Hayashi-cho, Takamatsu, Kagawa 761-0396, JAPAN.
Department of Chemistry, Faculty of Science, Okayama University of Science 1-1 Ridaicho, Kita-ku, Okayama 700-0005,JAPAN

Abstract
There are two types of mono-saccharide sugars in nature, which are natural monosaccharide and rare sugar. The sugar that exists in extreme few amount in nature is called as rare sugar e.g. D-psicose, D-allose. The reasons we choose the rare sugar as a research target are because the rare sugar has almost no calories and is very useful for diabetic and dieter patients. Specifically, D-psicose is a no-calorie rare sugar with the sweetness of about 70 % of a sucrose. It has been confirmed that taking the D-psicose with meals suppresses the rise of sugar into the blood. Further, it is very effective in improving and preventing the diabetes. In order to investigate a research on the rare sugars, the first step must be to obtain the correct molecular structure. However, few crystal structures of rare sugars have been reported up to now. Therefore, the purpose of this research is to analyze the single-crystal X-ray structure of unknown rare sugar -L-glucose-. In addition , the DV-Xαmolecular orbital method is used to compare the differences in a hydrogen bonding between D-glucose and L-glucose, and to make a novel supramolecular rare sugar.

Keywords
Rare Sugar, D-psicose, L-glucose, Supramolecule, Hydrogen bonding.

Topic
DV-Xa Method

Link: https://ifory.id/abstract/2tQaRPNTc4Jb

Corresponding Author
Jun Onoe

Institutions
Nagoya University, Tokyo Institute of Technology

Abstract
High-level radioactive nuclear liquid wastes (HLLW: radioactive metal ions in 2 M nitric acid solution) are generated in the reprocessing of spent nuclear fuels or in the decommissioning of nuclear reactors. In the process of producing the vitrified objects containing the wastes by using a glass melter, platinum-group metals (PGMs) [especially, ruthenium (Ru), rhodium (Rh), and palladium (Pd)] and molybdenum (Mo) cause serious problems: PGMs tend to be accumulated on the sidewall surface of the melter, whereas Mo compounds, so called yellow phase, are formed in the vitrified object. These issues result in (i) degradation of vitrified objects due to heterogenization and (ii) an increase in both disposal space and processing costs in conjunction with additional vitrified rods obtained by flushing the glass melter. To solve these issues, we have developed a process for efficient removal of PGMs and Mo from HLLW prior to introducing into the glass melter, using metal hexacyanoferrates (HCF) as a sorbent [1-3]. It is important to reveal the sorption mechanisms of PGMs and Mo for design of high performance HCF sorbents. In this talk, we will present the results on the sorption characteristics of Prussian blue (PB) nanoparticles, one of the HCFs, to the above metal ions in nitric acid solution, obtained using various spectroscopies and first-principles calculations. [1] S. Watanabe et al., J. Appl. Phys. 119, 235102 (2016). [2] S. Watanabe et al., AIP Adv. 8, 045221 (2018). [3] S. Watanabe et al., Chem. Phys. Lett. 723, 76–81 (2019).

Keywords
ferrocyanide nanoparticles, sorption characteristics, nuclear wastes, vitrification processes

Topic
DV-Xa Method

Link: https://ifory.id/abstract/HfgqyZTGFNEM

Corresponding Author
Masataka Mizuno

Institutions
Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Osaka University
2-1 Yamadaoka, Suita, Osaka 565-0871, Japan

Abstract
[Introduction & aim of the study] Recent experimental and theoretical studies suggest that the carbon-vacancy complexes are formed in Fe-C alloys. In this work, we have performed first-principles calculations to evaluate the stability carbon-vacancy complexes in α-Fe. For comparison, nitrogen-vacancy complexes have been investigated. [Method] We employed VASP code to obtain formation energies and stable structures of interstitial solutes Xn (X = C and N, n = 1 to 6) and vacancy (V) complexes. The chemical bonding was analyzed using DV-Xα molecular orbital calculations. [Results & conclusion] The formation energies of carbon-vacancy complexes have been calculated with reference to the total energy of an isolated interstitial atom and an isolated mono vacancy. In the case of carbon-vacancy complexes, the C2-V complex is most stable due to the energy gain by forming the C-C bonding. On the one hand, the N2-V complex is less stable than the N1-V complex. This is due to the repulsive interaction between N atoms. The overlap population analysis reveals that the C 2s – C 2s anti-binding interaction is reduced by the C 2s – C 2p bonding interaction. The interaction between the N 2s and N 2p orbitals is not strong enough to cancel the N 2s – N 2s anti-bonding interaction.

Keywords
Steel; defect; solute; interstitial; first-principles

Topic
DV-Xa Method

Link: https://ifory.id/abstract/eqfj6QtuFXLg

Corresponding Author
Prompong Pienpinijtham

Institutions
a) Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan.
b) Sensor Research Unit (SRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand.
c) Research Network NANOTEC-CU on Advanced Structural and Functional Nanomaterials, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.

Abstract
This work has investigated structural changes of graphene oxide (GO) in silver/graphene oxide (AGO) nanocomposites using tip-enhanced Raman scattering (TERS), which is a combination technique of surface-enhanced Raman scattering (SERS) and scanning probe microscopy (SPM). Based on SERS, a Raman spectrum of trace molecules adsorbed on rough metal surfaces/nanoparticles can be collected. On the other hand, nano-scaled topology of samples can be bestowed by SPM. As a result, TERS provides benefits of those two techniques, enabling one to determine molecular information of diminutive samples at specific nano-scaled areas. Because of this markedly high spatial resolution of the TERS technique, the structural changes of GO in AGO can be achieved by constructing line-profile TERS spectra straight from the center of silver nanoparticles (AgNPs) on GO layers. The results show evidences that AgNPs cause shortening of C–C bonds beneath AgNPs, flattening of GO layers, and critical bending on GO layers. Additionally, a connection of carbon atoms via C–C network subsequently expands structural changes with the distance of 200–250 nm from the center of AgNPs, even though this distance is larger than the size of AgNPs. The proposed model of GO structural changes opens new understanding about changes in properties from GO to AGO nanocomposites, which will contribute to a development of advanced nanostructures/nanocomposites in the near future.

Keywords
Tip-enhanced Raman scattering (TERS), Graphene oxide (GO), Silver nanoparticles (AgNPs), Silver/graphene oxide (AGO) nanocomposites, Structural changes.

Topic
DV-Xa Method

Link: https://ifory.id/abstract/bBUkwMf3WEA4

Corresponding Author
Katsumi Nakagawa

Institutions
MO BASICS Research

Abstract
Introduction) DV-Xa method uses numerical basis functions adaptable for the circumstance in a molecule. But they are calculated based on spherically symmetric potential for each atom. Newly proposed method inherits DV-Xa-s merit but isn-t restricted by the premise of atomic spherical symmetry. Aim of the study) This method is being developed as a powerful tool to calculate MOs under complicated outer potential, especially vector potential. Method) Basis functions are calculated by operations of matrices representing physical quantities and vectors representing wave functions. Analytical assists, like spherical harmonic functions, are not necessary at all. Hartree-Fock-Slater equations for molecules can be expressed numerically even for arbitrary outer potential and solved easily as eigenvalue problems of matrix. But basis functions for an atom are defined only on sample points proper to that atom. On the other hand, basis functions need to be defined on all sample points to calculate Fock matrices for LCAO-MO calculation. The author will explain some techniques to pass over this gap at this presentation. Results) LCAO-MO calculations were tested within real wave functions. Total energy vs interatomic-distance curves for N2, F2 and CO were calculated and showed minima near experimental equilibrium distances. Dipole moments of CO, O3 and NH3 were calculated and matched semi-quantitatively experimental moments. Calculations of basis functions were heavy but showed O(n) dependence. Conclusion) It was demonstrated that basis functions calculated by matrix operation can be used well for LACO-MO calculation. When wave functions are extended to complex, this method will serve as a useful tool to treat MOs under complicated magnetic fields.

Keywords
DV-Xa method, numerical basis functions, vector potential, dipole moment

Topic
DV-Xa Method

Link: https://ifory.id/abstract/DuBEr8k6VPbQ

Corresponding Author
Tomohiko Ishii

Institutions
Faculty of Engineering and Design,
Kagawa University

Abstract
We introduce rare sugars including their derivatives and supramolecular rare sugars, that have been actively researched at Kagawa University. Although rare sugars are special sugars which hardly exist in nature, we has succeeded in mass synthesis of rare sugars by utilizing biological enzyme isomerization reaction. In addition, rare sugars have various functions such as blood sugar level suppressing function, cancer cell growth suppressing function, and antibacterial action. In addition, since rare sugars have a large number of hydroxyl groups, they have a possibility for using as devices for expressing various functions by employing them as ligands of transition metal complexes. In recent years, it is successful that we have synthesized the suplamolecular rare sugars (SRSs) from the different types of rare sugars, that is not as simple mixtures but as single crystals having superlattice structure, that can be freely controlled optical rotation. It has been found that the crystal structures of these SRSs mostly follow the Wallach rule, but do not satisfy the Wallach rule especially in the case of D,L-psicose. Therefore, we have investigated the single crystal X-ray structural analyses of SRSs, obtaining the detailed crystal structure data, and analyzed the intermolecular interaction between their sugar molecules in the crystal by means of the DV-Xα molecular orbital calculation. According to our detailed analysis of the research, calculating the intermolecular interaction revealed that the stability of the intermolecular interaction in the crystal can not be explained only by following the simple Wallach rule. Specifically, for example in the case of D,L-psicose, the total energy in a crystal can be stabilized by aligning the polarization vectors of the molecules, and as a result, we have clarified that the SRSs crystal structure can be stabilized, even if it does not follow the simple Wallach rule.

Keywords
supramolecule, rare sugar, crystal structure

Topic
DV-Xa Method

Link: https://ifory.id/abstract/yYnwFg6G2uRH

Corresponding Author
Shota Takemura

Institutions
1- Department of Chemistry, Kwansei Gakuin University
2- Faculty of Engineering and Informatics, Universitas PGRI Semarang

Abstract
The position of the impurity level within the band gap is very important in optical materials. It can be estimated by calculating the charge transfer transition energy from the valence band to the impurity levels (Ligand to Metal Charge Transfer: LMCT). Recently, we successfully reproduced the LMCT energies and their experimental trend of transition metal (TM) ions in α-Al2O3 using the DVME method considering the configuration-dependent correction and the lattice relaxation based on the Shannons crystal radii. We also clarified that the LMCT energy is very sensitive to the bond length. In this work, in order to calculate the LMCT energies for various trivalent TM ions in α-Al2O3 using more accurate model clusters, we performed structural optimization using the CASTEP code and constructed the optimized TMO69- and TMAl13O630+ clusters (TM = Sc3+, Ti3+, V3+, Cr3+, Mn3+, Fe3+). As a result, the trend from Sc to V was reproduced better by calculations using the optimized clusters. The differences between the LMCT energies of the optimized clusters and those of the relaxed clusters based on the crystal radii originate from the multiplet splitting of the LMCT states.

Keywords
Charge transfer transition, Multiplet, Structural optimization

Topic
DV-Xa Method

Link: https://ifory.id/abstract/7EWU2qdL3pDm

Corresponding Author
Fatimah Salem Alluqmani

Institutions
2-1 Gakuen, Sanda 669-1337, JAPAN
Department of Chemistry,
School of Science and Technology,
Kwansei Gakuin University
(a) Student(D1)
(b) Professor

Abstract
Mn4+-doped oxide phosphors have been drawing attention as promising candidates for the red phosphors of white LEDs. However, since the desired emission wavelength has not been realized yet, a theoretical guideline to control the emission energy of Mn4+ in oxides is strongly desired. In this work, in order to clarify the energy-structure relationship of Mn4+ in oxides with D4h symmetry, we performed systematic first-principles calculations of multipllet energies for MnO6 clusters with gradually changed local structures using the discrete variational multi-electron (DVME) method. The variation of multiplet energies depending on two different bond lengths were clearly visualized by creating colored contour maps. In addition, in order to provide an easy-to-use predictive model of the multiplet energies of Mn4+ in oxides, we also performed a machine learning modeling by using the results of the systematic first-principles calculations as the training data. As a result, a simple theoretical model to predict the results of the first-principles calculation of Mn4+ in oxides with D4h symmetry was created. This model would be useful for development of novel Mn4+-doped oxide red phosphors since it enables one to predict the multiplet energies without performing complicated first-principles calculations.

Keywords
phosphor, white LED, first-principles calculation.

Topic
DV-Xa Method

Link: https://ifory.id/abstract/VGT7WuJctMwb

Corresponding Author
Deok-Yong Cho

Institutions
Department of Physics, Chonbuk National University

Abstract
X-ray absorption spectroscopy (XAS) is an easy and nice method to examine the chemical and local structural properties of materials which measures the X-ray absorption coefficients with various incident X-ray energies. XAS can reveal the atomic coordination and the intersite or intrasite electron-electron interactions for each atomic species, so that it can be commonly employed for identifying the local electronic structures of condensed matter. In this talk, I would like to overview the general principles of XAS for the local structural identification, and showcase some examples of theoretical considerations for metal oxide systems including manganites, double perovskite cobaltites and hafnia-zirconia. For the simulation of soft XAS spectra, the concept of configuration interactions with atomic multiplets is employed. For the simulation of hard XAS spectra (so-called XANES), the ab-initio real space multiplet scattering calculation (FEFF) is employed.

Keywords
X-ray absorption spectroscopy, XANES, FEFF, Configuration interactions, Atomic multiplets

Topic
DV-Xa Method

Link: https://ifory.id/abstract/Q4vLh6PgRGXK