Vibrational Predissociation Dynamics of the Nitric Oxide Dimer

Abstract

Details of experimental measurements of the total energy distribution and time dependence of the vibrational predissociation of the nitric oxide dimer are presented. Energy disposal measurements following v₁ excitation at 1870 cm⁻¹ indicated the fragments to be described by an average rotational energy <E_R>=75 cm^-1, full equilibration of the lambda doublet species, approximately equal populations in both spin-orbit states, no significant degree of alignment, an isotropic flux distribution, and an average kinetic energy of <E_K>=400 cm^-1 per fragment. Although approximately 75% of the available energy goes into fragment translation, picosecond laser pump - probe experiments showed that v ₁ decayed exponentially with a 880 ps lifetime. Excitation of v ₄ at 1789 cm⁻¹ gave a 39 ps predissociative lifetime.