RYDBERG ATOMS IN TIME-DEPENDENT ELECTRIC-FIELDS

An approximate representation of atomic states in a rapidly varying ti me-dependent electric field F(t) is presented, and its range of validi ty is explicitly determined. The approximation is tested for different time-dependent forms of F(t) by comparing with exact numerical soluti ons, where the field induced mixing is treated by including spherical hydrogenic states up to n less-than-or-equal-to 25 in the coupled equa tions. Within this validity range, the proposed formula describes the field dressed atomic wave functions surprisingly well, and improves wi th increasing principal quantum number of initial states. The formula has a wide range of applicability, and may be used to treat the effect s of fluctuating plasma dipole fields and externally imposed oscillati ng electric fields on atomic transitions.