Lattice Relaxation Effects on the Multiplet Energies of Ruby Under Pressure using One-Electron Calculations
Mega Novita (a*), Nur Cholifah (b), Kazuyoshi Ogasawara (c)
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