Multiphoton transition probabilities for potassium in strong parallel microwave and static fields

Abstract

We refine an earlier method for calculating the spectra of atoms and molecules in a strong microwave or laser field plus a static electric field. Results are reported for microwave resonance transition spectra of potassium for transitions from the 19s state at five choices of fixed microwave field strength (38, 68, 120, 152 and 193 V cm-1) as the static field strength is varied from 200 to 550 V cm-1. More resonances have been found in the higher microwave field-strength theoretical spectra than previously found experimentally. An understanding of butterfly-like structures in the plot of quasi-energy against static electric field strength has allowed an improved understanding of these novel features.