Femtosecond stimulated emission pumping: Characterization of the I{sub 2}{sup -} ground state

Journal Article · Mon May 22 04:00:00 EDT 2000 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.481499· OSTI ID:20216378

Zanni, Martin T ^[1]; Davis, Alison V ^[1]; Frischkorn, Christian ^[1]; Elhanine, Mohammed ^[1]; Neumark, Daniel M ^[1]

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1. Department of Chemistry, University of California, Berkeley, California 94720 (United States)

Femtosecond stimulated emission pumping in combination with femtosecond photoelectron spectroscopy is used to characterize the potential energy function of the I{sub 2}{sup -}(X(tilde sign) {sup 2}{sigma}{sub u}{sup +}) ground state up to vibrational energies within 2% of the dissociation limit. The frequency and anharmonicity of this state are measured at a series of vibrational energies up to 0.993 eV by coherently populating a superposition of ground state vibrational levels using femtosecond stimulated emission pumping, and monitoring the resulting wave packet oscillations with femtosecond photoelectron spectroscopy. The dissociative I{sub 2}{sup -}(A(tilde sign){sup '} {sup 2}{pi}{sub g,1/2}) state is used for intermediate population transfer, allowing efficient population transfer to all ground state levels. Using the measured frequencies and anharmonicities, the X(tilde sign) {sup 2}{sigma}{sub u}{sup +} state has been fit to a modified Morse potential with the {beta}-parameter expanded in a Taylor series, and the bond length, well depth, and {upsilon}=0-1 fundamental frequency set equal to our previously determined Morse potential [J. Chem. Phys. 107, 7613 (1997)]. At high vibrational energies, the modified potential deviates significantly from the previously determined potential. (c) 2000 American Institute of Physics.

• OSTI ID: 20216378
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 20 Vol. 112; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
ELECTRONIC STRUCTURE
EXPERIMENTAL DATA
GROUND STATES
IODINE IONS
PHOTOELECTRON SPECTROSCOPY
PUMPING
STIMULATED EMISSION