Journal of Physical Chemistry A, Vol.106, No.49, 11882-11890, 2002
Hot and cold clusters: Photodissociation of Sr+(CH3OD)(n) through vibrationally excited intermediates
This study presents photodissociation branching ratio data for clusters formed by solvation of Sr+ with CH3-OD molecules. The primary photoproducts in clusters with one to four solvent molecules are evaporative ligand loss, C-O bond cleavage to form SrOD+, and O-D bond cleavage, forming SrOCH3+. Careful analysis of the mass spectra of products and unphotolyzed parent ions as a function of laser fluence shows that clusters that lose a single solvent molecule may absorb additional photons, undergoing subsequent solvent evaporation and chemical reaction. Cluster ions formed by loss of one or more solvent molecules are vibrationally excited, and their subsequent photolysis products reveal strong enhancement of reactive channels involving D-atom loss and C-O bond cleavage relative to cold clusters produced directly by supersonic expansion. In addition to determining branching ratios for the products of vibrationally excited clusters, the study reveals that these hot clusters also have dissociation spectra that are strongly red-shifted relative to their cold counterparts.