Diode-Laser Measurements of He-Broadening Coefficients in the nu6 Band of 12CH3F
He-broadening coefficients are measured for 28 lines of 12CH3F in the RQ0 (Ki = 0, DeltaK = 1, DeltaJ = 0) and RQ6 (Ki = 6, DeltaK = 1, DeltaJ = 0) branches of the nu6 band, using a tunable diode laser spectrometer. The collisional widths obtained by fitting Rautian profiles to the measured shapes of the lines are slightly larger than those derived from Voigt profiles. The broadening coefficients for the lines belonging to the same low J transitions are significantly greater in the RQ0 branch than in the RQ6 branch. Moreover, they decrease on the whole with increasing J in the RQ0 branch and tend to increase from J varying from 7 to 10 in the RQ6 branch. These trends may be approximately reproduced by calculations based on a semiclassical impact theory of collisional broadening. Copyright 1997 Academic Press. Copyright 1997Academic Press
Grigoriev
IM
Unite mixte de recherche PALMS (Physique des Atomes, Lasers, Molecules et Surfaces), Universite de Rennes I, Batiment 22, Campus de Beaulieu, Rennes Cedex, F-35042, France
Bouanich
JP
Blanquet
G
Walrand
J
Lepere
M