Open AccessEffect of trivalent manganese substitution in α-Al2O3crystal on the absorption spectra based on first-principles calculations
Author(s) -
Mega Novita,
Duwi Nuvitalia,
Nur Cholifah,
Kazuyoshi Ogasawara
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1402/6/066004
Subject(s) - castep , bond length , chemistry , lattice energy , absorption spectroscopy , crystal (programming language) , lattice (music) , spectral line , crystal structure , crystallography , atomic physics , molecular physics , density functional theory , computational chemistry , physics , quantum mechanics , computer science , acoustics , programming language , astronomy
The absorption spectra of α-Al 2 O 3 : Mn 3+ at low-spin (LS) state have been estimated based on first-principles calculations without referring to any experimental parameter. The effect of lattice relaxation due to the Mn 3+ substitution was considered under several computational procedures such as the Shannon’s crystal radii method and the geometry optimization using Cambridge Serial Total Energy Package (CASTEP) code. Two different sizes of model clusters consisting of 7 and 63 atoms were compared. Next, the molecular orbitals (MO) were estimated using the one-electron calculations discrete variational-Xα (DV-Xα) method while the absorption spectra were estimated using the many-electron calculations discrete variational multi-electron (DVME) method. The results show that the lattice-relaxation ratio is about ca. 104.05-106.43% depending on the computational conditions. Due to the Mn-O bond-length elongation, the crystal field splitting (10 Dq ) decreased ca. 0.24-0.41 eV. Thus, the peak position originating from 3 T 1 → 3 E transition energy shifted toward the lower energy ca. 0.10-0.26 eV. Both of the larger-cluster size and the lattice-relaxation effect decrease the peak energies.