Microwave-Assisted Resonant Collisional Energy Transfer in Na Rydberg States

Abstract

Microwave-assisted resonant collisional energy transfer process $\mathrm{Na}\mathrm{}\left(\mathrm{ns}\right)+\mathrm{Na}\mathrm{}\left(\mathrm{ns}\right)+h\nu \to \mathrm{Na}\mathrm{}\left(\mathrm{np}\right)+\mathrm{Na}\mathrm{}\left(\right(n-1\mathrm{}\left)p\right)$ is observed between two colliding $\mathrm{Na}\mathrm{}\left(\mathrm{ns}\right)\mathrm{}$ atoms. The collisional resonance occurs when the microwave frequency $\nu$ equals the collisional energy defect $\frac{\Delta W}{h}$. The observed cross sections are very large (∼${10}^8$ ${\mathrm{\AA }}^2$) and require very low microwave power, ∼10 W/${\mathrm{cm}}^2$. These observations are in good agreement with an intuitive two-photon absorption model for these collisions.