Vibrational relaxation of CO+(Athinsp;2Pgr;i,vprime;=1) and CO+(Bthinsp;2Sgr;+,vprime;=1) ions in the collision with CO molecules

摘要

The vibrationally selected CO+(Athinsp;2Pgr;i,vprime;=0,1) and CO+(Bthinsp;2Sgr;+,vprime;=0,1) ions were generated by the photoionization of CO using Ne and He resonance lamps, respectively. The quenching cross sections of the excited ions were found to be very large and exceed gas kinetic values in theBthinsp;2Sgr;+state. In both excited states it has been observed that the vibrationally excitedvprime;=1 ion relaxes tovprime;=0 level through the collision with the parent CO molecules. The branching ratio of quenching to relaxation in thevprime;=1 ions was explained by a cascading relaxation mechanism in which all the vibrational levels underlying the excitedvprime;=1 level contribute to the energy transfer.