ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
A new quantum mechanical study on UV photodissociation of H2O2 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 A˜ and B˜ 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 A˜ and B˜ states are Gaussianlike with a maximum at j=8 on the A˜ surface and at j=9 on the B˜ surface at 248 nm. Similar distributions are found at 266 nm, but with the maximum shifting lower by approximately one quanta in both the A˜ and B˜ 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=j↘1+j↘2) distribution, which reflects the vector correlation of j↘1 and j↘2, is quite different on two surfaces. Our calculation shows that the A˜ surface gives rise to more bending excitation than the B˜ surface, reflected by a hotter j12 distribution on the A˜ surface. The A˜ and B˜ state branching ratio of H2O2 is also evaluated at 248 and 266 nm photolysis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.467130
