Molecular NO desorption from crystalline sodium nitrate by resonant excitation of the NO{sub 3}{sup -} {pi}{pi} transition

Journal Article · Thu Jul 27 04:00:00 EDT 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100030a015· OSTI ID:90959

Bradley, Jr, R A; Lanzendorf, E; McCarthy, M I; Orlando, T M; Hess, W P ^[1]

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1. Pacific Northwest Lab., Richland, WA (United States)

We have studied the laser desorption of NO from single crystal sodium nitrate following pulsed 213-nm excitation of the {pi}{sup *} {yields} {pi}{sub 2} absorption band localized on the nitrate anion. At low fluence, the NO photodesorption yield is found to be linear with desorption laser power indicating that single-photon absorption events lead to fragment ejection. The desorption yield is enhanced by roughly a factor of 1000 for resonant excitation (213 nm) over nonresonant excitation (266 nm) on a per-photon basis. We determine the relative vibrational, rotational, and translational energy distributions of the neutral NO photoproducts. Significant population in vibrational levels up to v{double_prime} = 4 is observed and translational distributions for the v{double_prime} = 0-3 levels are determined. A local excitation mechanism for NO desorption following resonant excitation is proposed. Under these experimental conditions the resonant desorption process (213 nm) is dominated by the photochemistry of the surface nitrate ions. A model for the absorption/dissociation mechanism is proposed that differs from that reported for gas phase ions in that it accounts for the stabilization of the ions due to the crystalline field. The role of exciton migration following resonant excitation is also discussed. 42 refs., 7 figs.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 90959
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 30 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
ABSORPTION SPECTRA
ANIONS
DESORPTION
LASER RADIATION
NITRIC OXIDE
PHOTOCHEMICAL REACTIONS
RESONANCE
SODIUM NITRATES