title: Optimization of nonlinear parameters in trial wave functions with a very large number of terms.
abstract: A procedure is proposed to construct highly accurate variational wave functions with large and very large numbers of basis functions. The procedure has a number of advantages in actual computations on parallel computer clusters. In particular, by using this procedure we have determined very accurate numerical values of the ground-state energies in the positronium ion Ps(-) (or e(-)e(+)e(-)) (E= -0.262 005 070 232 980 107 770 375 a.u.) and hydrogen ion infinityH(-) (E= -0.527 751 016 544 377 196 589 759 a.u.) The variational energies of the negative hydrogenlike ions (or H(-)-like ions) with the finite nuclear masses (T(-), D(-), 1H(-), and Mu(-)) are also presented. These energies are the best variational ground-state energies ever obtained for these ions.
authors.affiliation: Department of Applied Mathematics, University of Western Ontario, London, Ontario, Canada N6A 5B7.
authors.forename: Alexei M
authors.initials: AM
authors.lastname: Frolov