Electric-field-induced bound states and resonances in heteronuclear atomic collisions

The variations of the bound states of heteronuclear collision complexes in a static electric field are investigated. Using a prototype model, we engineer the interatomic interaction of the collision complex to have an $l$-wave bound state or quasibound state (virtual state for $s$ wave) close to the threshold. The variation of such a state with electric field is calculated to find out whether it crosses the threshold and produces a zero-energy resonance. We identify the cases in which an electric-field-induced resonance can occur at low field. The prototype model is used to interpret the calculated results with realistic potentials for heteronuclear alkali-metal collision complexes. We also calculate the probability density of the low-energy scattering state and find that the short-range probability density can still be enhanced in the absence of electric-field-induced resonance.