Photoionization dynamics of H₂ C ¹Π_u: Vibrational and rotational branching ratios

Journal Article · Thu Jan 01 04:00:00 EST 1987 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.453022· OSTI ID:6408113

O’Halloran, M. A. ^[1]; Pratt, Stephen T. ^[1]; Dehmer, Patricia M. ^[1]; Dehmer, Joseph L. ^[1]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)

Angle-integrated, rotationally resolved photoelectron spectra were determined for three-photon resonant, four-photon (3+1) ionization of H₂ via the C ¹Π_u, v' = 0--4 intermediate levels using a magnetic bottle electron spectrometer. The results confirm and extend our previous angle-resolved results obtained using a hemispherical electron energy analyzer. As predicted by both Franck--Condon factors and recent ab initio Hartree--Fock level calculations, ionizing transitions in which the vibrational level of the resonant intermediate state is preserved in the ion are most probable; however, large deviations from theoretical expectations are observed for photoionization of all intermediate levels. These deviations take the form of a progressive broadening of the ionic vibrational distribution as the vibrational level of the resonant intermediate state is increased. The rotational branching ratios also exhibit systematic variations with both the vibrational level of the C ¹Π_u state and the vibrational level of the ion. Photoelectron signal from ionization of electronically excited atomic hydrogen produced in the photodissociation of H₂ C ¹Π_u is also observed.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Health and Environmental Research; Office of Naval Research
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6408113
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 6 Vol. 87; ISSN JCPSA6; ISSN 0021-9606
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
BRANCHING RATIO
ELECTRON SPECTROMETERS
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY LEVELS
EXCITED STATES
HYDROGEN
IONIZATION
MEASURING INSTRUMENTS
MULTI-PHOTON PROCESSES
NONMETALS
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
ROTATIONAL STATES
RYDBERG STATES
SPECTROMETERS
SPECTROSCOPY
VIBRATIONAL STATES