The intramultiplet relaxation of Cd(5 3P2) by H2 and D2

Abstract

Intramultiplet mixing collisions of chromium 3d 54p 7 P 0 J with gases. Absolute cross sections and velocity dependence J. Chem. Phys. 80, 3137 (1984); 10.1063/1.447128Collisional intramultiplet relaxation of Cd(5s5p 3 P 0,1,2) by alkane hydrocarbonsThe deactivation processes ofCd(5 3P 2 ) by H2 and D2 were studied by employing pulsed laser techniques. The cross sections for the intramultiplet relaxation to produce Cd (5 3 PI ) and Cd (5 3 Po ) were determined as follows:Cd(5 3P 2 ) + H2 -Cd(5 3P I ) + H 2 ; 6.3, Cd(5 3P 2 ) + H2 -Cd(5 3p o ) + H 2 ; 1.0, Cd(5 3P 2 ) + D2 -Cd(5 3P I ) + D 2 ; 4.4, Cd(5 3P 2 ) + D2 -Cd(5 3P O ) + D 2 ; 0.9, in units of 10-16 cm 2 at 630 K. The cross sections for the overall deactivation ofCd(5 3P 2 ) by H2 and D2 were determined to be 9.8X 10-16 cm 2 and 6.9X 10-16 cm 2 , respectively. These values are compared with the calculated results based on a semiclassical curve crossing mechanism. It is suggested that electronic-to-rotational energy transfer without sharp resonances plays an important role in the deactivation ofCd(5 3P 2 ).

The intramultiplet relaxation of Cd(53P2) induced by collisions with4He,3He and Ar

“…The experimental apparatus and the procedures were similar to those reported elsewhere (Umemoto et a / 1990b(Umemoto et a / , 1991a. A mixture of Cd vapour and He or Ar in a T-shaped heat pipe oven was irradiated with XeCl laser pulses at 308 nm.…”

“…Collision-induced photoabsorption processes can be used to produce metastable species which cannot be produced by usual optical excitation. Recently, we have succeeded in producing metastable Cd(53P,) atoms selectively by .irradiating Cd-He collision complexes with the output of a XeCl laser at 308 nm (Umemoto et a/ 1990b(Umemoto et a/ , 1991a. It is possible to determine the cross sections for the intramultiplet relaxation of Cd(5'PJ by measuring the population ratios of the 53P,,,z states just after the excitation.…”

Cadmium (5 1 P 1 → 5 3 P J) excitation transfer and 5 3 P J intramultiplet relaxation by collisions with molecular gases

“…Umemoto et al [6] couldn't reproduce their measured cross sections with the help of a resonance model, either.…”

“…Collisions of excited cadmium atoms in various states of the 5s5p configuration with rare gases or molecular gases have attracted considerable attention in the past [1][2][3][4][5][6][7]. A major difficulty in the determination of the intramultiplet collisional cross sections arises from the relatively large fine structure separation of the lowest triplet states.…”

“…Recently Umemoto et al [6] succeeded in producing excited Cd(5 P ) atoms through optical excitation of a Cd-He complex, thus allowing to measure their collisional deactivation cross sections for H and D . Another approach, using direct optical excitation of the Cd(5 P ) state starting from the Cd(5 S ) ground state, analogous to the measurements of Bras et al [8] in the case of mercury, has been attempted in the course of the present investigation; it failed due to the very small transition probability of this highly forbidden transition.…”