SELF-BROADENING IN THE NU(1) BAND OF NH3

Self-broadening coefficients, pressure shifts and integrated intensiti es have been measured for Q- and R-branch transitions in the nu1 funda mental band of ammonia using a difference-frequency laser spectrometer . A strong, systematic J and K dependence of the broadening coefficien ts, reminiscent of the ground-state inversion transitions, is observed and compared with semiclassical line broadening calculations. Dicke n arrowing is evident at intermediate pressures for the sharpest lines, primarily the R(J, 0) transitions. Incipient line mixing is apparent i n the Q branch at pressures above approximately 0.1 bar.