Improvements in the generation and detection of Kr(3P) and Kr(3P2) atoms in a flow reactor: Decay constants in He buffer and total quenching rate constants for Xe, N2, CO, H2, CF4, and CH4

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Abstract
The generation and decay of Kr(3 P 2) and Kr(3 P 0) atoms in a flowing afterglow reactor at 300 K using He carrier gas have been characterized and compared with Ar carrier gas. The dominant loss for the Kr(3 P 2) and Kr(3 P 0) atoms in He is diffusion to and quenching at the wall; the two‐body quenching constants are of the order of 1×10−15 cm3 s−1 for each. The Kr(3 P 0) concentration in He carrier was sufficiently high that the total quenching rate constants were measured without resorting to optical pumping from the lower energy Kr(3 P 2) state. Room temperature rate constants are reported and the product states are discussed for the Kr(3 P 2) and Kr(3 P 0) reactions with Xe, CO, N2, H2, CF4, and CH4; the difference between the Kr(3 P 0) and Kr(3 P 2) rate constants for N2 is nearly a factor of 6. Quenching rate constants for 13CO are ∼25% smaller than those for 12CO. The Kr(3 P 0) reaction with CO gives mainly CO(b 3Σ+) and (e 3Σ−); the CO(b, v’=0) level is much more rotationally excited than CO(b, v’=1). Excitation‐transfer to Xe from Kr(3 P 2) gives mainly Xe(6p[3/2]2 and [3/2]1 ); the Kr(3 P 0) reaction favors the Xe(7s) states. A systematic study of the best electrode configuration and operating conditions for the dc discharge using He carrier gas is reported for the generation of Xe(3 P 2), Ne(3 P 0) and Ne(3 P 2), as well as Kr(3 P 2) and Kr(3 P 0).