THE STRUCTURE AND INTERMOLECULAR DYNAMICS OF THE NITROUS OXIDE-ETHYLENE COMPLEX - EXPERIMENT AND AB-INITIO THEORY

Optothermal infrared spectroscopy has been used to study the vibration al modes of N2O-C2H4 that correlate with vg of the ethylene monomer an d nu(1) + nu(3) in the N2O subunit. The results show that the N2O lies above the plane of the ethylene and in a rigid picture has its axis p arallel to the C=C bond. However, both bands show tunneling splittings that indicate that the two molecules rotate with respect to one anoth er about the axis through their centers-of-mass. Ab initio calculation s are in agreement with this, indicating that this is the only feasibl e tunneling path. The tunneling splittings are used in conjunction wit h a single axis, two rotor tunneling model to estimate the height of t he barrier to internal rotation. (C) 1996 American Institute of Physic s.