Electric field induced saturation effects in photoassociation of a pair of heteronuclear atoms

Abstract

We theoretically study saturation effects induced by an external static electric field on photoassociation (PA) of a heteronuclear atom pair. A static electric field influences scattering wave-function of two heteronuclear atoms as described in [D. Chakraborty, J. Hazra and B. Deb, J. Phys. B. {\bf 44} 095201 (2011)]. For certain values of electric field strengths there exist anisotropic resonances in ground state scattering leading to a large modification of scattering wave-function at short and intermediate separations where photoassociative Franck-Condon overlap is significant. Photoassociation rate as a function of collision energy shows a splitting near resonant electric field in the mili Kelvin energy regime. This splitting with a prominent dip occurs due to resonant enhancement of free-bound stimulated linewidth leading to saturation in free-bound transitions. We study electric field induced saturation effects on both one- and two-colour PA. Our results suggest that a static electric field may influence the formation of ground state polar molecules in two-colour PA.