Fine-structure mixing in72Dand82DRb atoms, induced in collisions with ground-state atoms and molecules

Cross sections for 7/sup 2/D and 8/sup 2/D fine-structure mixing in Rb, induced by collisions with various ground-state atoms and N/sub 2/ molecules, have been determined using methods of atomic fluorescence. Rb vapor, pure or mixed with a buffer gas, was irradiated in a glass fluorescence cell with pulses of radiation from a N/sub 2/ laser-pumped dye laser, populating a /sup 2/D fine-structure state by two-photon absorption. The resulting fluorescence included a direct component arising from the optically excited state and a sensitized component due to the collisionally populated fine-structure state. Measurements of relative intensities of the two components in relation to buffer-gas pressure yielded the following cross sections (in units of 10/sup -14/ cm/sup 2/): Q(7/sup 2/D/sub 3/2/..-->..7/sup 2/D/sub 5/2/) = 1 4.1, 15.5, and 10.0; Q(7/sup 2/D/sub 3/2/reverse arrow7/sup 2/D/sub 5/2/) = 9 .0, 10.5, and 6.9, for Kr, Xe, and N/sub 2/, respectively; Q(8/sup 2/D/sub 3/2/..-->..8/sup 2/D/sub 5/2/) = 8 .9, 4.9, 12.4, 24.9, 25.8, 12.1, and 43.1; Q(8/sup 2/D/sub 3/2/reverse arrow8/sup 2/D/sub 5/2/) = 5 .8, 3.2, 9.4, 15.1, 17.6, 8.3, and 28.5, for He, Ne, Ar, Kr, Xe, N/sub 2/, and Rb, respectively. Cross sections for the effective depopulation of the /sup 2/D states weremore » also determined.« less