Laser-induced gratings in free jets. III. Saturation-induced anharmonic gratings

Journal Article · Sat Jan 15 04:00:00 EST 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.466568· OSTI ID:5429050

Dunlop, J R; Rohlfing, E A ^[1]

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1. Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551 (United States)

We apply two-color laser-induced grating spectroscopy (LIGS) to obtain excitation spectra of the [ital S][sub 1]([ital [tilde A]] [sup 1][ital B][sub 1])--[ital S][sub 0]([ital [tilde X]] [sup 1][ital A][sub 1]) system of jet-cooled azulene. The ground-state depletion grating created by excitation with crossed beams is probed via either the [ital S][sub 2]([ital [tilde B]] [sup 1][ital A][sub 1])--[ital S][sub 0]([ital [tilde X]] [sup 1][ital A][sub 1]) or [ital S][sub 4]([ital [tilde D]] [sup 1][ital A][sub 1])--[ital S][sub 0]([ital [tilde X]] [sup 1][ital A][sub 1]) transitions. First-order LIGS spectra of the [ital S][sub 1]--[ital S][sub 0] origin band at several grating-laser intensities reveal saturation-induced line broadening and significant saturation dips at line center. We develop a simple model, based on the anharmonic grating created in the saturated regime, and use it to fit the first-order data. From these fits we determine a saturation parameter and the linewidth of the [ital S][sub 1]--[ital S][sub 0] origin absorption band, which is homogeneously broadened due to rapid internal conversion ([tau][similar to]1 ps) in the [ital S][sub 1] state. We also observe LIGS spectra of the azulene origin taken at the second Bragg order of the induced grating; the observed second-order lineshapes are also fit with the anharmonic-grating model.

• OSTI ID: 5429050
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 100:2; 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
ABSORPTION SPECTRA
AZULENE
BEAMS
COLLIDING BEAMS
COLOR
COOLING
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
GRATINGS
GROUND STATES
HYDROCARBONS
JETS
LASERS
LINE BROADENING
MULTI-PHOTON PROCESSES
NONLINEAR OPTICS
OPTICAL PROPERTIES
OPTICS
ORGANIC COMPOUNDS
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES
SATURATION
SPECTRA