Abstract
Interruption of the hyperfine interaction during electron spin-exchange collisions shifts the hydrogen-atom ground-state hyperfine transition frequency in proportion to the spin-exchange collision rate and to the average time during which the exchange interaction interrupts the hyperfine interaction. Measurements of the thermal average for hydrogen-hydrogen collisions at 308 °K in an atomic hydrogen maser confirm the predictions of a semiclassical theory and a numerical estimate using straight-line collision trajectories. Measurements of much longer for hydrogen-atom collisions with , NO, and N molecules are consistent with the formation of long-lived intermediate complexes during some collisions.
- Received 18 February 1975
DOI:https://doi.org/10.1103/PhysRevA.12.1305
©1975 American Physical Society