Photoacoustic measurement of differential broadening of the Lgr; doublets in NO(Xthinsp;2Pgr;1/2,v=2ndash;0) by Ar

摘要

A differential broadening of the Lgr; doublets in thev=2ndash;0 overtone band of the2Pgr;1/2ground electronic state of NO in an Ar buffer gas has been observed by photoacoustic spectroscopy using a tunable colorhyphen;center laser. The broadening coefficients for thefsymmetry components are larger than for theesymmetry components by up to sim;6percnt; forJsim;16.5. This differential depends onJand vanishes at lowJ, implicating the anisotropy of the unpaired electron Pgr; orbital in the plane of rotation. The2Pgr;3/2transitions are slightly broader than the2Pgr;1/2as a result of spinhyphen;flipping collisional relaxation. The observed line shapes also exhibit collisional or Dicke narrowing due to velocityhyphen;changing collisions.