Rotationally resolved photoelectron spectra in resonance enhanced multiphoton ionization of Rydberg states of NH

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463619· OSTI ID:7034949

Wang, K; Stephens, J A; McKoy, V ^[1]; de Beer, E; de Lange, C A; Westwood, N P.C. ^[2]

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1. Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125 (United States)
2. Laboratory for Physical Chemistry, University of Amsterdam, Nieuwe Achtergracht 127, 1018 WS Amsterdam (Netherlands)

Results of combined theoretical and experimental studies of photoelectron spectra resulting from (2+1) resonance enhanced multiphoton ionization (REMPI) via the {ital f} {sup 1}{Pi}(3{ital p}{sigma}), {ital g} {sup 1}{Delta}(3{ital p}{pi}), and {ital h} {sup 1}{Sigma}{sup +}(3{ital p}{pi}) Rydberg states of NH are reported. The overall agreement between these calculated and measured spectra is encouraging. Strong {Delta}{ital N}={ital N}{sup +}{minus}{ital N}{prime}=even peaks, particularly for {Delta}{ital N}=0, are observed in these spectra. Low-energy Cooper minima are predicted to occur in the l=2 wave of the {ital k}{pi}({sup 1}{Sigma}{sup +}), {ital k}{pi}({sup 1}{Sigma}{sup {minus}}), and {ital k}{pi}({sup 1}{Delta}) photoelectron channels for the {ital f} state, the {ital k}{pi}({sup 1}{Delta}), {ital k}{delta}({sup 1}{Pi}), and {ital k}{delta}({sup 1}{Phi}) channels for the {ital g} state, and the {ital k}{pi}({sup 1}{Sigma}{sup +}) and {ital k}{delta}({sup 1}{Pi}) channels for the {ital h} state of NH. Depletion of the {ital d} wave (l=2) contributions to the photoelectron matrix element in the vicinity of these Cooper minima subsequently enhances the relative importance of the odd l waves. The observed {Delta}{ital N} transitions are also affected by strong l mixing in the electronic continuum induced by the nonspherical molecular potential. Interference of continuum waves between degenerate ionization channels also determines the spectral pattern observed for photoionization of the {ital f} {sup 1}{Pi} state of NH. Photoelectron angular distributions and the angular momentum compositions of photoelectron matrix elements provide further insight into the origin of these Cooper minima.

• OSTI ID: 7034949
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 97:1; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
AUGMENTATION
COOPER PAIRS
ELECTRON SPECTROSCOPY
ENERGY LEVELS
EXCIMER LASERS
EXCITED STATES
GAS LASERS
HYDRIDES
HYDROGEN COMPOUNDS
IONIZATION
LASERS
MULTI-PHOTON PROCESSES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
PRODUCTION
RADICALS
RESOLUTION
RESONANCE ABSORPTION
ROTATIONAL STATES
RYDBERG STATES
SORPTION
SPECTROSCOPY