Speed dependent rotational angular momentum polarization of the O{sub 2} (a {sup 1}{delta}{sub g}) fragment following ozone photolysis in the wavelength range 248-265 nm
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ (United Kingdom)
The translational anisotropy and rotational angular momentum polarization of a selection of rotational states of the O{sub 2} (a {sup 1}{delta}{sub g}; v=0) photofragment formed from ozone photolysis at 248, 260, and 265 nm have been determined using the technique of resonance enhanced multiphoton ionization in combination with time of flight mass spectrometry. At 248 nm, the dissociation is well described as impulsive in nature with all rotational states exhibiting similarly large, near-limiting values for the bipolar moments describing their angular momentum alignment and orientation. At 265 nm, however, the angular momentum polarization parameters determined for consecutive odd and even rotational states exhibit clear differences. Studies at the intermediate wavelength of 260 nm strongly suggest that such a difference in the angular momentum polarization is speed dependent and this proposal is consistent with the angular momentum polarization parameters extracted and reported previously for longer photolysis wavelengths [G. Hancock et al., Phys. Chem. Chem. Phys. 5, 5386 (2003); S. J. Horrocks et al., J. Chem. Phys. 126, 044308 (2007)]. The alternation of angular momentum polarization for successive odd and even J states may be a consequence of the different mechanisms leading to the formation of the two O{sub 2} (a {sup 1}{delta}{sub g}) {lambda} doublets. Specifically, the involvement of out of plane parent rotational motion is proposed as the origin for the observed depolarization for the {delta}{sup -} relative to the {delta}{sup +} state.
- OSTI ID:
- 21024185
- Journal Information:
- Journal of Chemical Physics, Vol. 127, Issue 11; Other Information: DOI: 10.1063/1.2775453; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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