Microwave Ionization of Na Rydberg Levels

Abstract

The authors have observed the ionization of Na Rydberg states by strong microwave fields and have found that the field required for ionization is $\frac{1}{(3.7{n}^{5})}$ (in atomic units) for $n=20\ensuremath{-}37$. This field is close to the field $\frac{1}{(3{n}^{5})}$ at which the Stark manifolds of principal quantum numbers $n$ and $n+1$ intersect. The ionization can be shown to arise from transitions occurring near these intersections.