Molecular Orbital Calculation for BaTiS3.

Abstract

A crystal structure of BaTiS 3 has been widely investigated, and it was found that BaTiS 3 crystallizes a hexagonal BaNiO 3 structure and the unit cell contains two BaTiS 3 formulas (Hahn and Mutschke, 1956 ; Clearfield, 1963 ; Aslanov and Kovba, 1964 ; Huster, 1980). Huster (1980) found that the unit cell of BaTiS 3 has the space group D 4 6h (P6 3 / mmc) by using a 4-circle-diffractometer. In this case, Ba, Ti and S occupy Wyckoff positions 2d, 2a and 6h respectively. On the other hand, physical properties of this compound have not been almost researched. Even though there is a report by Aslanov and Kovba (1964) that BaTiS 3 was a semiconductive, the suf-ficient explanation was not given for the behavior. To clarify the nature of this compound, first of all, the important thing is to obtain the correct information about its electronic structure. However, no report is so far available about the electronic structure of BaNiO 3 -type structure. In the present work, we have performed a first-principles molecular orbital (MO) calculation for BaTiS 3 by discrete vari-ational Xa (DV-Xa) method (Adachi et al., 1978) and have elu-cidated the electronic structure of this compound. 2.̙Calculation Method