Abstract: The vibrational distributions of CNX~2Σ~+ have been obtained in photolysis of BrCN at 193 nm. An obvious increase of v″=1 population was found with increasing the collision of CN and BrCN. The populations in the v″=2—5 also appeared after the tens collisions. The case can not be found in photolysis of ClCN. A possible explanation was suggested that the CN radical is excited vibrationally due to a recoil which occurs at the collision of CN X~2Σ~+, v″=0 radical carrying 1.5 eV energy with the heavy molecule BrCN. This is similar to the vibrational excitation of CO at collision with a high speed H atom.