An experiment which yields a value of 6.6×105Torr−1sec−1for the vibration‐vibration decay rate of thev=2 state in HF gas is described. The technique involves observation of the rise time of the HFv=2 vibrational fluorescence emanating from a gas sample pumped with a HF laser operating on av=1→v=0 transition. An analytic model which predicts the temporal behavior of the HFv=1 and collisionally populatedv=2 vibrational levels is also described. This model predicts an apparent decay rate of thev=2 fluorescence, which is twice that forv=1. Experimental measurements confirm this prediction.