Study on energy transfer induced by collisions between rubidium and cesium

As two main atomic alkalis, rubidium (Rb) and cesium (Cs) have the similar energy-level structures. The energy transfer caused by collisions between rubidium and cesium atoms is a crucial factor for a vapor system. When such a vapor is irradiated with one component of rubidium resonance doublet, energy transfer will be induced by inelastic collisions between the excited rubidium atoms and the unexcited rubidium atoms, and between the excited rubidium atoms and the unexcited cesium atoms as well. It is noteworthy that the energy transfer between atomic rubidium and cesium is performed as cross relaxation. In this study, we theoretically investigate the effects of cross relaxations between the upper-state levels of atomic rubidium and cesium on the population distribution of the gas media. It has been demonstrated that the intensity of cross relaxations in this system is too weak to greatly affect the population distributions of atomic rubidium and cesium under the different temperatures. The conclusion might be helpful to better understand the physical features of alkalis.

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