Laser studies of electronic excitation transfer in atomic calcium:  Ca(4 s 5 p  1 P 1)+Ar⇄Ca(4 s 5 p  3 P 2, 1, 0)+Ar

Time-resolved nsec kinetic methods are used to measure state specific electronic excitation transfer for the near-resonant process: Ca(4s5p 1P1) +Ar ⇄k-1k1 Ca(4s5p 3P2,1,0)+Ar. In stimulated emission experiments it is found that the Ca(4s5p 3P2) level is preferentially populated. The rate constant k1 for the specific 3P2 channel is 5.2±0.5×10−11 cm3 molecule−1 sec−1. These results are discussed in terms of near-resonant spin changing collision mechanisms. Radiative lifetimes for Ca(4s5p 1P1) and Ca(4s5p 3P1) are also determined to be 77±2 nsec and 67±2 nsec, respectively.