Volume 119, Issue 19, 15 November 2003
Index of content:
119(2003); http://dx.doi.org/10.1063/1.1624246View Description Hide Description
The trans–perp conformer of peroxynitrous acid is identified by action spectroscopy in the OH overtone region and assigned by simulating its band structure using a transition moment and rotational constants from ab initiotheory. The highest observed OH product state sets an upper limit for the O–O bond energy of tp-HOONO of 16.8 kcal/mol.
119(2003); http://dx.doi.org/10.1063/1.1624833View Description Hide Description
We describe an experimental approach to the determination of the nascent internal state distribution of gas-phase products of a gas–liquid interfacial reaction. The system chosen for study is atoms with the surface of liquid deuterated squalane, a partially branched long-chain saturated hydrocarbon, The nascent OD products are detected by laser-induced fluorescence. Both OD and were observed in significant yield. The rotational distributions in both vibrational levels are essentially the same, and are characteristic of a Boltzmann distribution at a temperature close to that of the liquid surface. This contrasts with the distributions in the corresponding homogeneous gas-phase reactions. We propose a preliminary interpretation in terms of a dominant trapping-desorption mechanism, in which the OD molecules are retained at the surface sufficiently long to cause rotational equilibration but not complete vibrational relaxation. The significant yield of vibrationally excited OD also suggests that the surface is not composed entirely of endgroups, but that secondary and/or tertiary units along the backbone are exposed.
State-to-state photodissociation dynamics of OH radical via the state: Fine-structure distributions of the product119(2003); http://dx.doi.org/10.1063/1.1624247View Description Hide Description
Photo-predissociation dynamics of rotational states of are studied using high-nRydberg atomtime-of-flight technique. Spin–orbit branching fractions of are measured: for in and for in in excellent agreement with the recent theory. While predissociates predominantly via a single state, decays via the and states, and interferences of these dissociation pathways strongly influence the fine-structure distributions. is obtained.