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Hyper Rayleigh and hyper Raman scattering from ammonium chloride and ammonium bromide
Author(s) -
French M. J.,
Hall R. J. B.,
Long D. A.,
AlRubaiey F. M. F.
Publication year - 1985
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250160608
Subject(s) - raman spectroscopy , raman scattering , rayleigh scattering , ammonium bromide , ammonium chloride , chemistry , crystal (programming language) , wavenumber , bromide , ammonium , infrared , analytical chemistry (journal) , inorganic chemistry , optics , physics , organic chemistry , pulmonary surfactant , biochemistry , computer science , programming language
The hyper Rayleigh and hyper Raman (0–1600 cm −1 wavenumber shift) spectra of oriented single crystals of ammonium chloride and ammonium bromide are reported. It is demonstrated that hyper Rayleigh scattering is a very sensitive measure of the presence of a centre of symmetry within a crystal structure and this property is used to investigate the residual ordering within an ammonium chloride crystal at 55 K above the order‐disorder phase transition. The hyper Raman wavenumber shifts associated with the transverse (TO) and longitudinal (LO) components of the optic mode, the librational mode which is infrared and Raman inactive, and the H–N–H internal mode were observed for both crystals. A basis for the interpretation of the relative hyper Raman intensities of the LO and TO modes is provided by an extension of the Poulet treatment of the relative intensities in the Raman spectrum.