Abstract

In this two-photon process, the H₂ molecule is excited from the ground vibrational level (v_g = 0; j_g= 0) of the x′Σ_g state to different vibrational levels (v_i = 0,1,2, j_i = 1) of the B′Σ_u state and thereafter either to the lowest autoionizing state of ′Σ_g(1σu²) symmetry or directly to the ionization continuum (${\text{H}}_2^{+}:x^2{\Sigma }_g$; v_l = 0,1, 2; j_l = 0). Energy of the autoionizing state is −0.4632 a.u., which corresponds to the turning point R = 2.4 a.u. The wavelengths required for the above transitions are 1100 and 1500 Å, respectively. Resolvent operator technique has been used to obtain photoelectron (PE) angular distribution.^1,2 The laser bandwidth (γ_L) has been found to have different spectacular effects on PE angular distribution depending on laser intensities and also on the relative magnitude of the bandwidth compared to the spontaneous decay width (γ_a) of the intermediate resonant state. Moreover γ_L affects the PE angular distribution differently for transitions combining different intermediate (v_i, j_i) and final vibrational levels (v_l, j_l). Significant departure from the usual feature [≈1 + βP₂(cosθ)] for PE angular distribution was noticed for larger bandwidths.

© 1986 Optical Society of America