An experimental investigation of rare gases pressure effects on the rovibrational line intensities of HCl

A measurement method has been set up for the accurate determination of vibration–rotation line strengths. It has been applied to a careful analysis of the intensities of HCl lines pressurized by Ar or Xe. Several mixtures have been studied corresponding to pressures of the perturber ranging from 5 to 15 atm. It is shown that the line intensities S appear to vary linearly (within the accuracy of experimental measurements) with the density of the perturbing species. For each one of the investigated lines, a least squares fit allows one to retrieve the ’’standard’’ S0 value corresponding to pure HCl and excellent agreement with previous determinations is obtained. In addition, the rate of variation of S as a function of the density of the rare gas is determined and shown to be strongly m dependent.