ELECTRONIC SPECTROSCOPY AND QUENCHING DYNAMICS OF OH-H-2/D-2 PRE-REACTIVE COMPLEXES

摘要

Binary complexes of OH X (II)-I-2 and H-2/D-2 have been stabilized in the entrance valley to the hydrogen abstraction reaction and identified in the OH A (22)Sigma(+)-X (II)-I-2 0-0 spectra region. Nearly all of the intermolecular vibrational levels supported by the OH A (2) Sigma(+) (v'=0)+H-2/D-2 potential. energy surface have been observed in fluorescence depletion experiments. Rapid electronic quenching precludes the observation of OH-H-2/D-2, prepared in these levels by laser-induced fluorescence. A sharp onset of laser-induced fluorescence occurs at the OH A (2) Sigma(+) (v'=0)+H-2/D-2 dissociation limit. The binding energies for OH-H-2/D-2 in the ground state correlating with OH X (II)-I-2 (v''=0)+H-2/D-2 have been determined to be 54 cm(-1) and more than 66 cm(-1), respectively. The OH A (2) Sigma(+) (v'=0)+H-2/D-2 excited state is found to be at least 577 cm(-1) (H-2) and 639 cm(-1) (D-2) mom strongly bound than the ground state. The positions of observed features are compared with the corresponding intermolecular levels observed by laser-induced fluorescence in the OH A-X 1-0 region as well as theoretical predictions of the transition energies based on ab initio potentials for the ground and excited electronic states. The OH-H-2/D-2 intermolecular levels correlating with OH A (2) Sigma(+) (v'=0)+H-2/D-2 have lifetimes of 3.2-4.5 ps, deduced from homogeneous linewidths, due to quenching and/or chemical reaction. (C) 1996 American Institute of Physics. [References: 46]