State resolved photodissociation of vibrationally excited water: Rotations, stretching vibrations, and relative cross sections
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (US)
The state resolved photodissociation of highly vibrationally excited water molecules using laser induced fluorescence detection of the OH product demonstrates the control that the initially selected state exerts over product state populations. These vibrationally mediated photodissociation experiments, in which one photon prepares a highly vibrationally excited molecule and a second photon dissociates it, determine the role of overall rotations and of O--H stretching vibrations as well as measure the relative cross section for the photodissociation of water. The {ital rotational} {ital state} of the vibrationally excited water molecule governs the rotational state of the OH product of the dissociation, in agreement with {ital ab} {ital initio} calculations and previous measurements on single rotational states excited in the fundamental asymmetric stretching vibration band. The initially selected {ital vibrational} {ital state} of the water molecule determines the vibrational energy disposal in the products, which agrees with a simple qualitative model based on the pattern of the initially selected vibrational wave function. Dissociating vibrational states with similar energies but very different nuclear motions produces dramatically different product vibrational state populations. The vibrational energy initially present in the surviving bond primarily appears as vibrational excitation of the product. Dissociation of the {vert bar}04{r angle}{sup {minus}} state produces no vibrationally excited OH, but dissociation of the {vert bar}13{r angle}{sup {minus}} state produces mostly vibrationally excited products.
- OSTI ID:
- 6188321
- Journal Information:
- Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 94:3; ISSN JCPSA; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Vibrationally mediated photodissociation of hydrogen peroxide
Two-color vibrationally mediated photodissociation of nitric acid