Knowledge Bank

We have studied rates of vibrational energy transfer in $H2$-additive gas mixtures using a stimulated Raman-ir fluorescence technique. The doubled output of a $Nd+3$:YAG laser focused through a high pressure cell of $H2$ (at 5 atm) produced stimulated Stokes radiation. The laser and Stokes beams were then refocused into a second cell containing a low pressure $H2$-additive gas mixture. A small percentage of $H2$ ground state molecules were pumped to the $H2(v=1)$ level, thus allowing vibration to vibration energy transfer rates to be obtained by monitoring the rise and fall of the additive gas ir-fluorescence. The additive gas we have studied are HCl, DCl, DBr, $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}CO$, $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CO$, NO, $CO2$, and $N2O$. The pressures of the additive gases studied ranged, from 0.4 to 200 Torr with $H2$ pressures varying between 75 and 700 Torr. Results for some of the above mentioned gases mixtures will be presented in detail.