Linear- and circular-polarization photoionization angular distributions in H2 and H2+ by attosecond xuv laser pulses

Numerical solutions of the time-dependent Schrodinger equation, using a new unitary numerical method, are used to obtain gauge-independent photoionization angular distributions for two-dimensional (planar) models of aligned H-2 and H-2(+) molecules in different electronic states. Simulations are performed with few-cycle attosecond (as) extreme-ultraviolet (xuv) laser pulses at wavelengths lambda = 10 nm [omega = 4.56 a.u. (atomic units), tau = 2 pi/omega = 1.38 a.u. = 33.4 as], and lambda = 5 nm (omega = 9.11 a.u., tau = 16.7 as) for linear and circular polarization ionizations at R-e = 1.675 a.u., where molecular orbital configurations dominate for which the electronwavelengths lambda(e) >= R-e and at large internuclear distance R = 10 a.u. (lambda(e) < R) where Heitler-London atomic configurations including ionic states H+H- are more appropriate. The simulations allow one to investigate the effects of electron correlation and entanglement in H-2 at different R due to electron spin exchange as compared to the delocalized one-electron H-2(+) system. An ultrashort (delta function) pulse model is used to interpret interferences in momentum distributions.