Pump/Probe measurement of V-V transfer in O$_{2}$ and H$_{2}$

We present new sets of V-V rate coefficients for vibrational levels 0 -- 5 in O$_{2}$ and H$_{2}$ at 300 K, using a stimulated Raman -- spontaneous Raman pump/probe apparatus. For O$_{2}$ it is found that previously reported semi-classical trajectory calculations of Coleti and Billing underestimate the V-V rate coefficients by approximately one order of magnitude, in agreement with recent measurements by of Kalogerakis and the earlier observations of Diskin. For H$_{2}$ non-resonant processes, comparison with recalculated semi-classical predictions using the identical potential to that given by Cacciatori and Billing results in predicted rates which are too fast, by a factor of $\sim $2.5, consistent with the previously reported value of Kreutz. However for the ``resonant'' V-V process, H$_{2}$ (v=1) + H$_{2}$ (v=1) --$>$ H$_{2}$ (v=2) + H$_{2}$ (v=0), predictions are found to be too slow, by a factor of approximately two, consistent with previous reported data of Farrow and Chandler. This suggests that semi-classical calculation methods that treat the rotational motion classically may be unsuitable for H$_{2}$, due to rotational energy level spacings which are comparable to k$_{B}$T.