Knowledge Bank

The purpose of the investigation is to determine the behavior of a single type of variational parameter as the basis function becomes more complex. The molecule used for an example is $He2+$. The basis function is made more complex by successively considering one, two, and three different orbital exponents. The variation is performed at all values of the internuclear distance, in contrast to previous work which had been done only at the equilibrium internuclear distance. For comparison purposes, a variational-perturbation calculation is also performed on $He2+$.