Spectroscopic Study of Molecular Vibrational Energy in Phase-Changing Process.

Abstract

The vibrational energy of molecules in phase-changing processes was studied by measuring the infrared absorption spectra with FTIR (Fourier transform infrared) spectrometer. IR spectra of (NO)2 (ν1, ν4), CO2(ν2, ν3), N2O(ν1, ν2, ν3), and C2H2 (ν3, ν5) were Compared in the gas, Cluster, and solid phases. Absorptions of solid-phase molecules are observed at a blue or red shifted band from those in the gas phase, but in the clustering phase they are always blue shifted compared with those in solid phase. This leads to two kinds of vibrational energy changes in the phase-changing process from gas to solid ; blue and red shift, and red and red shift. These results observed can be explained reasonably by the vibrational mechanism of the ε, σ and m effects which characterize the effective potential and mass of molecules.