title: Argon-induced pressure broadening, shifting, and narrowing in the CN A2Π-X2Σ+ (1-0) band.
abstract: Selected isolated rotational transitions in the 1-0 band of the red A(2)Π-X (2)Σ(+) system in CN have been recorded with transient frequency modulation spectroscopy as a function of argon pressure up to 0.2 atm at room temperature. Line shapes were fit using Fourier transforms of a parametrized time correlation function, including Doppler and velocity-dependent collisional broadening, and collisional shifts. Deviations from Voigt line shapes can be equally well fit by modeling the narrowing with a speed-dependent collision model or with a velocity-changing collisional narrowing model. Pressure broadening coefficients were observed with little rotational state dependence, in the range of 0.070-0.075 cm(-1) atm(-1). In contrast, stronger and qualitatively different rotational state dependences are observed for both pressure-dependent blue shift coefficients and the narrowing parameters. No asymmetry in the pressure broadened lines was observed.
authors.affiliation: Chemistry Department, Brookhaven National Laboratory , Upton, New York 11973-5000, United States.
authors.forename: Damien
authors.initials: D
authors.lastname: Forthomme
authors.forename: Christopher P
authors.initials: CP
authors.lastname: McRaven
authors.forename: Trevor J
authors.initials: TJ
authors.lastname: Sears
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Hall