Inelastic Neutron Scattering and Far IR Spectroscopy of Acetonitrile in Solid Ar and CCl4 Matrices

Inelastic neutron scattering has been applied for the first time to the study of matrix isolated species whose thermodynamically stable phase under normal conditions is the liquid. The aims of these investigations, which are complemented by far infrared studies, are to explore the aggregational behaviour of acetonitrile and the intermolecular dynamics of the respective aggregates in low temperature matrices of solid Ar and CCl4. The only aggregate observed, using a variety of different spectroscopic techniques and diverse experimental conditions, is an antiparallel dimer. In contrast to the external intermolecular modes of this aggregate, which were not accessible by vibrational spectroscopy, the internal modes could be described and assigned.