Structure and vibrational dynamics of tetragonal NaBi(WO4)2 scheelite crystal
1996; Elsevier BV; Volume: 12; Issue: 1 Linguagem: Inglês
10.1016/0924-2031(96)00006-9
ISSN1873-3697
AutoresJ. Hanuza, A. Benzar, A. Haznar, Mirosław Mączka, A. Pietraszko, J.H. van der Maas,
Tópico(s)Optical and Acousto-Optic Technologies
ResumoThe structure of tetragonal NaBi(WO)2 crystal is determined. The space group is I4̄S2/2 with cell dimensions a = 5.275, c = 11.493 Å and two molecules per unit cell. The tungsten atoms occupy two different sites of 4̄ symmetry. Also Bi and Na atoms statistically occupy two positions with different occupancy factors. The IR and polarized Raman spectra are discussed on the basis of factor group analysis and normal coordinate calculations. Urey-Bradley force field and potential energy distribution were used in description of the normal modes. The polarization behavior of vibrational spectra is explained and related to the crystal structure.
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