FOURIER-TRANSFORM INFRARED MATRIX-ISOLATION STUDY OF ACETONITRILE IN SOLID ARGON

The intramolecular fundamental vibrations of CH3CN trapped in solid argon matrix have been reinvestigated by means of FT-IR spectroscopy in the spectral range of 40000-500 cm-1. By employing a quantum detector, infrared spectra could be obtained ate matrix to solute ratio of 10000, allowing the clarification of the peaks due to monomeric species more clearly. Temperature controlled diffusion was initiated to identify the dimeric and polymeric species in terms of difference spectra. The assignments of monomeric and dimeric species are found, in general, to agree with the earlier work performed at higher concentration (Ar/CH3CN=1500) using a dispersive spectrometer. Nonetheless the difficulty of minute differences between the earlier infrared and Raman spectroscopic results could be resolved. Moreover, the previously unnotified peaks due to polymeric species have been identified.