Electron correlation in doubly excited states of the hydrogen molecule

The electron correlation in some low-lying doubly excited states of the ${\mathrm{H}}_{2}$ molecule is investigated by analyzing two-body correlation functions in comparison with the corresponding doubly excited states of He. Effects of increasing the internuclear distance and of avoided crossings are discussed. Some interesting features of electron-correlation patterns are found to appear because of the additional symmetries of the molecule. Autoionization widths of the doubly excited states are evaluated and the autoionization mechanisms are analyzed in connection with the electron correlation.