Temperature dependence of self broadening of ammonia transitions in the v₂ band

Self broadening coefficients have been measured as a function of temperature from 192 to 377 K for five transition lines of the nu(2) band of ammonia at similar to 937 cm(-1). The results have been compared with theoretical calculations performed in the semiclassical impact approximation, and although one hot transition does not fit well in this scheme, there is in general a fairly good agreement. Moreover there is also an experimental and theoretical evidence against the commonly assumed power law for the temperature dependence. More measurements are needed to clarify the position of the hot transitions in this respect and to verify the extent of validity of the power law in general.