Vibrational spectra of arsenic triiodide

Abstract

The Raman spectrum of AsI₃ has been determined in solution in CS₂ and in the solid state. For the solution the assignment of Stammreich, Forneris, and Tavares has been confirmed by polarization studies. In the solid state it is shown that assignment of the spectrum is only possible on the basis of space group symmetry and an earlier assignment based on point group C_3v is in error. The solid state frequencies (R3 symmetry) are _v1(A_g) 185 cm^-l, v₂(A_g) 75 cm^-l, v₃(A_u) 201 cm^-l, v₄(A_u) 102 cm^-1, v₅(E_g) 205 cm^-1, v₆(E_g) 50 cm^-l, v₇(E_g) 216 cm^-1, v₈(E_g) 74 cm^-1.