Infrared spectra of solid HCl and HBr. The overtone region

摘要

Infrared spectra of solid HCl and HBr have been investigated in the second and third overtone regions at several temperatures and pressures. The overtone spectra have been interpreted in terms of longhyphen;wavelength onehyphen;phonon rsquo;rsquo;proper harmonics,rsquo;rsquo; i.e., excitation to higher vibrational levels in the same molecules, and twohyphen;phonon excitations involving molecules in neighboring sites with different phases. In hydrogen bonded solids like HCl and HBr the two spectra are well separated. Additional spectral structure is explained as combinations with lattice modes. The effect of phase transformation from the disordered orthorhombic to the ordered orthorhombic phase of solid HBr on its spectrum has also been investigated.