Infrared and Raman spectral studies and normal modes of α-Bi2O3

Infrared and Raman spectra for α-Bi2O3 have been recorded at 300 K and 85 K and analysed in detail. α-Bi2O3 belongs to the monoclinic system, to space group P21/c. From the factor group analysis, 60 lattice vibrations are distributed as 15Ag, 15Bg, 15Au and 15Bu modes of the group. The observed IR and Raman frequencies are assigned to the various vibrational modes and an analysis of the lattice vibrations is carried out by the Wilson GF matrix method using a least-squares fit technique. The analysis makes it possible to completely describe the fundamental modes of α-Bi2O3 and leads to a force field which can be transferred to other systems containing Bi and O atoms.