Premium
A study of the torsional modes in ethylammonium chloride, bromide and iodide as a function of temperature
Author(s) -
Ratcliffe C. I.,
Sherman W. F.,
Wilkinson G. R.
Publication year - 1982
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.1250130215
Subject(s) - chemistry , raman spectroscopy , halide , bromide , iodide , chloride , steric effects , atmospheric temperature range , inorganic chemistry , thermodynamics , stereochemistry , organic chemistry , physics , optics
Raman spectra of the torsional and lattice modes in single crystals of the chloride, bromide and iodide salts of the ethylammonium ion, C 2 H 5 NH 3 + , have been obtained over the range between liquid nitrogen and room temperatures. Corresponding infrared spectra of the torsional modes of the salts in caesium halide discs have also been obtained at the two temperature extremes. In general the modes all show an apparently linear decrease in frequency with increasing temperature. The torsions show relatively large splittings between their Raman and infrared components, due to interactions between adjacent rotors in the lattice. A two‐rotor model has been applied to attempt to quantify the principal threefold barriers to rotation and the interaction potential constants for both the NH 3 +and CH 3 rotors. The torsional frequencies and barriers reflect the changing effects from one salt to another, of hydrogen bonding and steric forces in the lattice.