Laser Raman and infrared spectra of Rochelle salt crystals

Abstract

Abstract A systematic analysis of the IR and Raman spectra of Rochelle salt (NaKC 4 H 4 O 6 · 4H 2 O) in terms of the standard frequency correlations, deuteration shift and typical nature (with respect to intensity and width) of bands due to different modes is reported. The bands due to the internal modes (excluding some skeletal modes) of the C 4 H 4 O ion appear as doublets. For certain modes [e.g. β CH , ν C(OH) and δ COO ] doublets arise owing to interactions between two identical oscillations of two identical groups in COO(HO)HCCH(OH)COO 2− , while for other modes (e.g. ν CH , ν , ν , δ COH and τ COO ) they arise owing to crystallographically distinguishable sites for two identical oscillators.