SINTERED DISC SPECTRA OF SOME AMMONIUM $HALIDES^{*}$

Abstract

The infrared absorption spectra of $NH_{4}Cl$, $NH_{4}Br$ and $NH_{4}I$ have been investigated in sintered discs of NaCl, KCl, KBr, KI, RbCl, and CsCl at room temperature and $-195^\circ C$. The discs were prepared from both mechanical and coprecipitated mixtures of $NH_{4}X$ and alkali halides. The spectra do not necessarily correspond to those obtained from sublimed films of ammonium halides. The spectrum of the $NH_{4}^{+}$ ion is determined by the structure of the alkali halide, whether the material is mixed mechanically or coprecipitated. The ammonium halides and alkali halides appear to form solid solutions. The sintered disc technique offers a convenient method for determining infrared band intensities in the solid state. Some preliminary results on $NH_{4}Cl$ are described.