The photodissociation of ClO{sub 2}: Potential energy surfaces of OClO{r_arrow}Cl+O{sub 2}
- Department of Chemistry, Washington State University, Richland, Washington, 99352 (United States)
- Institut fuer Theoretische Chemie, Universitaet Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)
Using large multireference configuration interaction wave functions, potential energy surfaces involved in the photodissociation of symmetric ClO{sub 2} to Cl+O{sub 2} are investigated. The production of atomic chlorine from OClO, which may have important implications for stratospheric ozone chemistry, is predicted to occur via the excited 1{sup 2}{ital B}{sub 2} electronic state after initial excitation to the {ital A}{sup 2}{ital A}{sub 2} state. A calculated {ital C}{sub 2{ital v}} transition state connecting 1{sup 2}{ital B}{sub 2} OClO to Cl+O{sub 2} is strongly bent and has a barrier height relative to the {ital X}{sup 2}{ital B}{sub 1} ground state of 2.86 eV (2.75 eV with zero-point vibrational corrections). However, this is only a 2nd-order transition state with imaginary vibrational frequencies along both the OClO{r_arrow}Cl+O{sub 2} and OClO{r_arrow}ClO+O reaction paths (symmetric bending and asymmetric stretching modes, respectively). Thus, the present theoretical work suggests that only a small amount of Cl+O{sub 2} will be formed in the photodissociation of ClO{sub 2} due to the dominance of the ClO+O channel. Much of the O{sub 2} that is produced is predicted to be in the {ital a}{sup 1}{Delta}{sub {ital g}} state, since the 1{sup 2}{ital B}{sub 2} potential energy surface in {ital C}{sub 2{ital v}} symmetry correlates with this state of O{sub 2}. However, other nearby electronic states of OClO, namely the 1{sup 2}{ital A}{sub 1} and 2{sup 2}{ital B}{sub 2}, interact in the exit channel and will facilitate the production of especially {ital X}{sup 3}{Sigma}{sup {minus}}{sub {ital g}} and perhaps {ital b}{sup 1}{Sigma}{sup +}{sub {ital g}} O{sub 2}, respectively. The present results are in very good accord with the recent photofragment translational energy spectroscopy experiments of Davis and Lee [J. Chem. Phys. {bold 105}, 8142 (1996)]. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 401128
- Journal Information:
- Journal of Chemical Physics, Vol. 105, Issue 22; Other Information: PBD: Dec 1996
- Country of Publication:
- United States
- Language:
- English
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