The effect of elastic and reorientation collisions on vibration-rotation lineshapes: A semi-empirical approach

Collisional broadening of rotation-vibration spectral lines is investigated. The contributions from inelastic and elastic-reorientation collisions are separated using a semi-empirical inversion procedure. The basis for this deconvolution is the derivation of a relationship between the enelastic, Wⁱⁿ, and elastic-reorientation, W^el-r, contributions to the width, which depends upon a single unknown parameter. The experimental linewidth, W^exp = W^el-r + Wⁱⁿ, suffices to determine this parameter uniquely, which is then used to calculate the individual components W^el-r and Wⁱⁿ. Results of applications to the CO-, HF-, and HCI- rare gas systems are presented.