A variational function for the ground state of H₂⁺

For the ground state of the H 2 + molecule the function ψ = (1 + pR ξ) exp (-α R ξ) cosh (β R η) which is separable into elliptic coordinates, has been studied. The calculated energy is lower than that of any of the existing variational functions. The integrals <X 2 > and <Z 2 >, as well as the energy values for different nuclear separations, have also been calculated.