Model for V→ T, R relaxation: CH4 and CD4 mixtures

A laser‐fluorescence technique is used to determine vibration‐to‐vibration energy transfer rates for relaxation of $\mathrm{HCl}\text{\hspace{0.17em}(v=1)}$ and $\mathrm{DCl}\text{\hspace{0.17em}(v=1)}$ by CH₄ and CD₄. The rates of subsequent vibration‐to‐rotation and translation relaxation of the bending vibrations of CH₄ and CD₄ by several collision partners are measured. These data are interpreted in terms of a model which includes rotational motion of both collision partners, as well as relative translational motion. The variation of deactivation probabilities with the mass parameter, ${\mathrm{(\mu }}^{†}{)}^{\text{−1}}{\mathrm{=m}}^{\text{−1}}{\mathrm{+A}}_1{\mathrm{(\mu }}_{\text{R1}}{)}^{\text{−1}}{\mathrm{+A}}_2{\mathrm{(\mu }}_{\text{R2}}{)}^{\text{−1}}$ , and temperature qualitatively indicates the relative importance of rotation and translation in each deactivation process.