Specific heat and frequency shifts for the translational modes in ammonia solid I close to phase transition

Spectrochim Acta A Mol Biomol Spectrosc. 2007 Jul;67(3-4):1060-6. doi: 10.1016/j.saa.2006.08.046. Epub 2006 Sep 28.

Abstract

The specific heat C(p) is correlated to the frequency shifts (1/nu)( partial differentialnu/ partial differentialT)(p) in ammonia solid I close to the melting point. Our calculated Raman frequencies for the translational modes of nu(T) (100 cm(-1)) and nu(T) (130 cm(-1)), are used for this correlation for the pressures of 0, 1.93 and 3.07 kbar in this crystalline system. We obtain that the specific heat varied linearly with the frequency shifts for those pressures studied and values of the slope dP(m)/dT were extracted. The observed behaviour of the ammonia solid I near the melting point is explained on the basis of our spectroscopic modification of the first Pippard relation.

MeSH terms

  • Ammonia / chemistry*
  • Crystallization
  • Hot Temperature*
  • Phase Transition*
  • Pressure
  • Spectrum Analysis, Raman
  • Transition Temperature*

Substances

  • Ammonia