Ground-state energy ofHeH+

Abstract

The nonrelativistic ground-state energy of $^{4}\mathrm{He}{\mathrm{H}}^{+}$ is calculated using a variational method in Hylleraas coordinates. Convergence to a few parts in ${10}^{10}$ is achieved, which improves the best previous result of Pavanello et al. [J. Chem. Phys. 123, 104306 (2005)]. Expectation values of the interparticle distances are evaluated. Similar results for $^{3}\mathrm{He}{\mathrm{H}}^{+}$ are also presented.