Resonance-enhanced one- and two-photon ionization of water molecule: Preliminary analysis by multichannel quantum defect theory

Journal Article · Mon Feb 01 00:00:00 EST 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.464224· OSTI ID:6942092

Vrakking, M J.J.; Lee, Y T ^[1]; Gilbert, R D; Child, M S ^[2]

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1. Chemical Sciences Division, Lawrence Berkeley Laboratory, and Department of Chemistry, University of California at Berkeley, Berkeley, California 94720 (United States)
2. Department of Theoretical Chemistry, University of Oxford, 5 South Parks Road, Oxford OX1 3UB (United Kingdom)

Experimental results are presented for one- and two-photon ionization of the water molecule, obtained using a near transform-limited xuv laser. The single-photon ionization results show rotationally resolved autoionizing resonances corresponding to members of Rydberg series ([ital nd][l arrow]1[ital b][sub 1]; [ital n]=6--11) converging on the H[sub 2]O[sup +](100) vibrational state. The two-color (1+1) multiphoton ionization results show rotationally resolved structure corresponding to Rydberg series ([ital nd][l arrow]1[ital b][sub 1]; [ital n][ge]6) converging on the H[sub 2]O[sup +](000) vibrational state. Typical linewidths below and above the H[sub 2]O[sup +](000) ionization threshold are 1 and 2 cm[sup [minus]1], respectively. The experimental results are simulated by multichannel quantum defect theory (MQDT). The main features in the spectrum are reproduced in a treatment of the rotational channel interactions with partial [ital l] mixing. It is argued that remaining discrepancies between experiment and theory arise from perturbative interactions between the ([ital nd][l arrow]1[ital b][sub 1]) levels and members of the ([ital nd][l arrow]3[ital a][sub 1]) Rydberg series. Also, it is argued that in the (1+1) multiphoton ionization spectra lines may be missing due to selective predissociation.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6942092
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 98:3; ISSN JCPSA6; 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
AUTOIONIZATION
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
EXCITED STATES
EXTREME ULTRAVIOLET RADIATION
HYDROGEN COMPOUNDS
IONIZATION
LASERS
MECHANICS
MULTI-PHOTON PROCESSES
OXYGEN COMPOUNDS
PHOTOIONIZATION
QUANTUM MECHANICS
RADIATIONS
RESOLUTION
RESONANCE
ROTATIONAL STATES
SIMULATION
ULTRAVIOLET RADIATION
VIBRATIONAL STATES
WATER