高平动能(1.15 eV)CN基的T-V过程的探讨

用193毫微米光解BrCN和ClCN的研究,发现一些很有意义的结果。如在光解BrCN时发现碎片CN X~2∑~+ v″=0的转动能级高达80以上,它可研究高转动能在传能和反应中的作用。研究中发现一些异常现象;Heaven等在扩散分子束中得到BrCN的光解产物CN X~2∑~+,共中v″=0约占80%,v″=1约占20%;而Halpern等在10~(-5)Torr延迟0.2微秒测得的光解产物,v″=0占94%,v″=1占6%。Heaven给出的谱图上出现很高的P_(0,0)支带头,与Halpern结果比较,明显地发生了转动弛豫,达表明实验中有碰撞弛豫。但为什么v″=1的布居不下降,却反而上升?为了弄清达个问题,我们在不同BrCN压办及不同延迟时间下去探测CN X~2∑~+,v″的碰撞弛豫。

DISCUSSION ON THE T-V PROCESS IN CN RADICAL WITH HIGH TRANSLATION ENERGY (1.5 eV)

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.