Gaussian functions in Hylleraas-configuration interaction calculations. II. Potential curves for the b 3Σ+u and the e 3Σ+u states of hydrogen

The Hylleraas-CI method with Cartesian Gaussian basis functions has been used to calculate the potential energy curve of the repulsive b 3∑+u state of the hydrogen molecule at internuclear distances R ranging from 1.0 to 12.0 bohrs. At small R, sizable improvements over the best previous calculations using elliptical coordinates are reported. The potential curve for the bound e 3∑+u state is also reported, as a by-product since it compares very well with the best conventional CI results.