Testing Lineshape Models: Measurements for v = 1-0 CO Broadened by He and Ar
We present measurements of the spectral profiles of many P and R branch lines in CO-He and CO-Ar mixtures, all at 301.5 K. The lineshapes are compared with several semi-classical models and in particular with models that include the speed dependence of both the translational motion and the relaxation of the optical coherence. Using a correlated speed-dependent Galatry model proposed by Ciurylo and Szudy we find an apparent reduction of the Dicke narrowing, amounting to almost 100% in some cases with a strong dependence on the rotational quantum number. However, while the parameters of this and several other models may be adjusted to fit the experimental data within the noise, no single model is free of criticism. Several shortcomings of existing models are discussed. Plots of broadening coefficients versus line number are also given. Copyright 1997 Academic Press. Copyright 1997Academic Press
Duggan
P
Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario, M5S 1A7, Canada
Sinclair
PM
Berman
R
May
AD
Drummond
JR