The effect of polarization on the light-induced conical intersection phenomenon

It has already been shown that dressing of diatomic molecules by standing or running linear polarized laser waves gives rise to conical intersections (CIs). Due to the presence of such CIs, the rovibronic molecular motions are strongly coupled. Here we prove that only perfect linear polarized light induces CIs in diatomic molecules. However, the fingerprints of the light-induced conical intersection survive for an elliptical polarization but not for a circular polarization. Therefore, the effects of the light-induced conical intersection can be controlled by varying a physical parameter (polarization of the laser). Such a CI controllable physical parameter does not exist in field-free polyatomic molecules. An illustrative numerical example for a sodium dimer showing the dependence of the absorption spectrum of Na(2) upon ellipticity is given