Effect of pressure and temperature on the Raman spectra of solid N2O

Raman studies as a function of pressure (P<40 GPa) and temperature (T=20–300 K) have been made of the external and internal modes of solid N2O The occurrence of orientational disorder manifests itself in the line shape of the lattice and intramolecular modes. A new high pressure phase N2O–II was found above 5.5 GPa. The pressure dependence of external and internal modes is determined. The temperature shift of the external modes is found to decrease drastically with increasing pressure. The available data from the experiments are used to obtain some information about the contributions of the explicit and implicit terms to the total temperature shift. Analysis of the Fermi resonance shows that pressure strongly weakens Fermi resonance which is not influenced by temperature.