Two-Center Effects In One-Photon Single Ionization Of H-2 (+), H-2, And Li-2 (+) With Circularly Polarized Light

We present a theoretical study of one-photon single ionization of H-2 (+), H-2, and Li-2 (+) with circularly polarized light of a few hundred eV (a few tens of eV for Li-2 (+)). At these photon energies, two-center interference effects due to confinement and double-slit diffraction are expected. The results show that, in general, the calculated angular distributions for circularly polarized light are very similar to those obtained by incoherently averaging the angular distributions for parallel and perpendicular linearly polarized light. Thus, at the lower photon energies, the multiple lobes observed in the angular distributions for circularly polarized light (which are absent for linearly polarized light) have little to do with confinement and/or double-slit diffraction. At the higher photon energies, such effects do exist, but they are partly hidden and are much more difficult to analyze than for linearly polarized light. The simple diffraction interpretation is even less applicable for H-2 and Li-2 (+) because confinement and double-slit diffraction appear at electron energies too low to ignore electron correlation and the details of the molecular potential.