We study theoretically the Feshbach-optimized photoassociation of the
7Li and
133Cs atoms driven by electric and magnetic fields. The results show that the combination of electric and magnetic fields can significantly enhance the photoassociation rate by regulating scattering resonance and increasing the probability density of atom pairs at sufficiently short internuclear distance. The electric field can induce the coupling between the
s wave and
p wave and makes it possible to directly produce ultracold molecules in the lowest rotational state via one-photon stimulated emission photoassociation at ultralow temperature. Moreover, in the presence of a magnetic field, only a relatively weak electric field ($E\ensuremath{\le}100$ kV/cm) is required to realize the scattering resonance for heteronuclear alkali-metal atom pairs.
The effects of an electric field on the magnetically induced
6Li-
40K Feshbach resonances are investigated theoretically by using the asymptotic bound-state model. We calculate the positions and widths of the Feshbach resonances observed in the experiments in the presence of an electric field and give a detailed analysis. An electric field can change the relative magnetic moment and the coupling strength to a different extent. The variation of resonant width caused by a strong electric field mainly depends on the coupling strength, and the
s-wave scattering cross section in an electric field is sensitive to the temperature of the colliding system and the magnetic-field intensity. The maximum of the thermal average scattering rate constant can be changed by several factors by applying an electric field.