POLARIZED INFRARED-SPECTRA OF AMMONIUM HYDROGEN BIS-CHLOROACETATE IN THE PARAELECTRIC PHASE

The polarized IR spectra of ammonium hydrogen bis-chloroacetate in the paraelectric phase have been measured. The antisymmetric stretching vibration, nu-(a)OHO, of the strong hydrogen bond gives rise to a very intense and broad absorption appearing in the ac face spectra and in the spectrum polarized along the b axis. For this vibration a correlation field splitting is observed. The deformation delta-OHO vibration appears as a broad, intense band at about 1590 cm-1 polarized at 120-degrees in the ac face spectra. The interaction between the nu-(a)OHO and nu-C = O modes is observed. The NH4+ ion has C2 symmetry in the paraelectric phase, although its nu-1 stretching vibration does not conform to the C2 selection rules.