title: Infrared-infrared double resonance spectroscopy of the isomers of acetylene-HCN and cyanoacetylene-HCN in helium nanodroplets.
abstract: Infrared-infrared double resonance spectroscopy is used to probe the vibrational dynamics of molecular complexes solvated in helium nanodroplets. We report results for the acetylene-HCN and cyanoacetylene-HCN binary complexes, each having two stable isomers. We find that vibrational excitation of an acetylene-HCN complex results in a population transfer to the other isomer. Photoinduced isomerization is found to be dependent on both the initially excited vibrational mode and the identity of the acetylene-HCN isomer. However, population transfer is not observed for the cyanoacetylene-HCN complexes. The results are rationalized in terms of the ab initio intermolecular potential energy surfaces for the two systems with particular emphasis on the long-range barriers to rearrangement.
authors.affiliation: Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA. douberly@uga.edu
authors.forename: Gary E
authors.initials: GE
authors.lastname: Douberly
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Merritt
authors.forename: Roger E
authors.initials: RE
authors.lastname: Miller