Temperature dependence of self-shift of ammonia transitions in the v₂ band

Pressure-induced lineshift has been measured as a function of temperature, in the range 200-400 K, for five transitions of the v2 band of ammonia lines near 937 cm-1. Results are compared with semiclassical calculations that rely on the impact approximation. In general the theory does not agree very well with the experimental values of the shift, but the sign and the order of magnitude are confirmed. The present work shows that extensive and detailed measurement of the lineshifts is feasible and reliable, even when their absolute values in ammonia as a function of temperature are very small. Copyright (C) 1996 Elsevier Science Lt