Alignment sensitivity of molecular-frame photoelectron momentum and angular distribution of H_(2)^(+) by XUV attosecond pulses

In this work,we investigate the molecular-frame photoelectron momentum and angular distributions(MF-PMD and MF-PAD)of H_(2)^(+) in the presence of XUV Attosecond Pulses.We present the alignment-sensitive effect of MF-PMDs and MF-PADs when the laser field polarization and the molecular axis are close to parallel geometry.Our results show that the MF-PADs and MF-PMDs of single-photon ionization of H_(2)^(+) ion vary drastically when the alignment slightly shifts from parallel geometry to a small alignment angle(e.g.4°)between the laser polarization direction and the molecular axis at the equilibrium inter-nuclear distance of R_(c)=2 atomic units.As R_(c) increases to 4 atomic units,such sensitivity is decreased.The R_(c)-dependent transition cross-sections in different channels are found to be the origin of such sensitivity.