Quantum dynamical studies for photodissociation of H2O 2 at 248 and 266 nm

Zheng T. Cai, Dong H. Zhang, John Z.H. Zhang

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Abstract

A new quantum mechanical study on UV photodissociation of H 2O2 at 248 and 266 nm using a 2D fit to the Schinke-Staemmler's (SS) potential energy surface (PES) [Chem. Phys, Lett. 145, 486 (1988)] is reported. The rotational distributions of the product OH on both the à and B̃ surfaces are found to be considerably hotter than those obtained in a previous quantum study [J. Chem. Phys. 98, 6276 (1993)] using an empirical PES with a very weak dependence on the torsional angle φ. The new calculation shows that the rotation distributions in both the à and B̃ states, are Gaussianlike with a maximum at j=8 on the à surface and at j=9 on the B̃ surface at 248 nm. Similar distributions are found at 266 nm, but with the maximum shifting lower by approximately one quanta in both the à and B̃ states. The dissociation preferentially produces OH rotations with a high j1∼j2 correlation. These conclusions are in excellent agreement with the classical calculation of Schinke-Staemmler at 193 nm photolysis. Although the j distribution (rotation of OH) is similar on both surfaces, the J12(j 12 = J1 + J2) distribution, which reflects the vector correlation of J 1 and j2, is quite different on two surfaces. Our calculation shows that the à surface gives rise to more bending excitation than the B̃ surface, reflected by a hotter j 12 distribution on the à surface. The à and B̃ state branching ratio of H2O2 is also evaluated at 248 and 266 nm photolysis.

Original languageEnglish (US)
Pages (from-to)5631-5638
Number of pages8
JournalThe Journal of Chemical Physics
Volume100
Issue number8
DOIs
StatePublished - 1994

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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