Correlation-function hyperspherical harmonic calculations of the pp, dd, and tt molecular ions

The direct solution of the Schrödinger equation for the ground state of the pp, dd, and tt molecular ions is obtained with the help of the correlation-function hyperspherical harmonic method. Given the proper correlation function, chosen from physical considerations, the method generates wave functions, accurate in the whole range of interparticle distances, which leads in turn to precise estimates of the expectation values of the Hamiltonian and of different functions of interparticle distances. Our results are compared with those obtained in other precision calculations.