Lattice Dynamics in Ammonium Perchlorate.

The breakdown of the crystal lattice of ammonium perchlorate in the 300-625 K range has been studied by laser Raman spectroscopy. Detailed examination of the external and internal modes of the ion reveals that the onset of essentially unhindered tumbling of the ClO4- ion seems to be intimately tied to the decomposition of AP. The effect of K as an isomorphous dopant in the crystal lattice is to permit the ClO4- ion to tumble at a lower temperature 0.8 K produces a 60-70 K lowering in the tumbling temperature and thus decompose at a lower temperature. Pressure effects on AP at 300 K show normal behavior and we do not believe that pressure plays a very large role in the decomposition of the crystal. All vibrational modes found in ammonium perchlorate including several not here-to-fore reported are discussed and insofar as possible assigned.