Predissociation lifetimes of OH A sup 2. Sigma. sup + ( v prime =3) obtained from optical--optical double-resonance linewidth measurements

Journal Article · Fri Nov 15 00:00:00 EST 1991 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.461433· OSTI ID:5045914

Gray, J A; Farrow, R L ^[1]

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1. Combustion Research Facility, Sandia National Laboratories, Livermore, California (USA)

The excitation of rapidly predissociating {ital v}{prime}=3 levels in the {ital A} {sup 2}{Sigma}{sup +} state of OH has recently been suggested as a means of avoiding collisional quenching corrections when performing laser-induced fluorescence (LIF) measurements in flames. We report measurements of predissociation rates of several rotational levels in {ital v}{prime}=3, obtained from linewidths in optical--optical double-resonance (OODR) spectra. The magnitude of the observed predissociation rates places an upper limit on the pressures at which OH LIF can be considered quench-free.'' In addition, analysis of spectral line shapes suggests that {ital rotational} {ital transfer} can significantly affect LIF quantum yields at pressures of 1 atm and higher. We conclude that variations of the predissociation rate with rotational level in {ital v}{prime}=3 must be included in determinations of rotational temperatures from LIF.

• OSTI ID: 5045914
• Journal Information: Journal of Chemical Physics; (United States), Vol. 95:10; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HYDROXIDES
PREDISSOCIATION
DOUBLE RESONANCE METHODS
DYE LASERS
ENERGY TRANSFER
EXCITATION
FLUORESCENCE
LIFETIME
LINE WIDTHS
MEDIUM PRESSURE
ROTATIONAL STATES
TUNING
VIBRATIONAL STATES
YIELDS
DISSOCIATION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
HYDROGEN COMPOUNDS
LASERS
LIQUID LASERS
LUMINESCENCE
OXYGEN COMPOUNDS
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory