Doubly excited autoionizing states of H_2 above the second ionization threshold: the Q_2 resonance series

摘要

We report extensive calculations of energy positions, autoionization widths and branching ratios for the Q_2 doubly excited states of H_2 lying above the second ionization threshold ~2#SIGMA#_u~+. We present results for 60 doubly excited states of the ~(1,3)#SIGMA#_(g,u)~+, ~(1,3)#PI#_(g,u), and ~(1,3)#DELTA#_(g,u) symmetries in the range of internuclear distances 0 <= R <= 6 a.u. The resonance parameters have been obtained using the Feshbach theory and an L~2 representation of the nonresonant continuum with B-spline functions. Our results are compared with previous theoretical data. We have found significant discrepancies for states of the ~1#SIGMA#_g~+ and ~1#SIGMA#_u~+ symmetries.