Mercury 6 3P J relaxation and intramultiplet mixing under collisions with H2, HD, D2, and He

Abstract

Absolute rate constants for quenching and intramultiplet mixing of Hg(63P0,1,2) by collisions with H2, HD, and D2 have been determined. A smooth variation of these coefficients with the isotopic form of hydrogen has been observed. For He only an upper limit of the rate constants has been obtained. Attempts to explain the 3P1←3P2 transfer by simple mechanisms are described. The surface crossing mechanism seems the most adapted. But a theory more elaborate than the one presented here should be developed, including both the rotational and the vibrational degrees of freedom of the molecule.

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

“…'.2) just after the excitation. The rate equations corresponding to the above mechanism are given as follows if the excitation is instantaneous: (12) (13) …”

“…[18][19][20] have also applied this approach to the intramultiplet relaxation of Hg (6 3 P 2 ) by isotopic hydrogens. 12 The cross sections for the intramultiplet relaxation of Cd(5 3P 2 ) to produce Cd(5 3P I ) were calculated semiclassically, following the computational procedure presented by Bras et al 12 Time dependent Schrodinger equations were solved by assuming linear trajectories. The quadrupole moments ofH2 and D2 were taken from literature values.…”

“…Since we underestimated the potential energy of the ~ state of CdHe in our previous work, newly developed potentials were employed. 8 • 22 The Hamiltonian matrix can be block diagonalized into three parts, by employing the basis states presented by Bras et al 12 The transition probability for each block can be calculated as functions of collisional velocity and impact parameter. The calculated transition probability diverges when the impact parameter is very small.…”

“…H2/D2 isotope effect has also been observed for the fine-structure transitions in Hg( 6 3 P J ), Ca(4 3P J ), and Rb(S 2P J ). 12,15,19 Cuvellier Cd(S 3P 2 ) + H2 (J = 4) -+Cd(S 3P 1 ) + H2 (J = 6). The energy discrepancy, I!…”

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

“…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.…”