Transient vibrational dynamics in condensed phase reactions

Transient infrared methods are used to observe directly fast reactions and vibrational relaxation processes in solution with high spectral resolution. Bimolecular reactions of the CN radical are observed following photolysis of ICN in chloroform. The CN radicals react with solvent molecules to form HCN. In the deuterated solvent, some of the nascent DCN molecules are formed in a vibrationally excited state, which constitutes the first-observation of vibrationally excited products in a condensed phase bimolecular reaction. In a second experiment, photolysis of s-tetrazine in solution creates vibrationally hot HCN in a unimolecular reaction. Deuterated s-tetrazine creates an initially inverted vibrational distribution of DCN products. Both experiments indicate that the dynamics of reactive barrier crossings and vibrational energy redistribution are significantly altered upon solvation.