New results for the temperature dependence of self-broadening and shift in the v2 ammonia band

Self-collisional broadening and shift parameters are measured by diode-laser spectroscopy for the v2 ammonia transitions aP(6,1), aP(6,0), aP(2,1), aQ(9, 9), aQ(11,10), aQ(4,1) and aQ(8,5) whose frequencies range between 816 and 934 cm-1. The temperature dependence of these lineshape parameters is studied in the range 200-400 K. Experimental results are compared to semiclassical calculations which are quite reliable for the broadening and for its temperature trend, while some discrepancies are found for the magnitude of the shift. A power-law temperature dependence fits well the broadening parameters; for the temperature dependence of the shift different models are compared. The separate e!ect of translational and rotational temperature on the two lineshape parameters is discussed