Search

Hylleraas–configuration interaction (CI) calculations have been carried out with double-linked basis sets for the Be atom. Our best upper bound for the 1S ground state is E0 = −14.6673547Eh. Furthermore, upper bounds for the two lowest excited 1S states have been calculated. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 66: 241–247, 1998

Highly accurate upper bounds for several 2Pe states of the Li isoelectronic series obtained by extensive Hylleraas-Cl calculations are given. The best value for the 22Pe state (1s2p2) of Li is −5.21373920 au. The evaluation of the occurring integrals is given explicitly. Additionally, we present some expectation values and isotope energies of the Li isoelectronic series. © 1997 John Wiley & Sons, Inc.

Atomic Hylleraas-CI calculations with liked correlation terms of the form r{sub ij}{sup p}r{sub kl}{sup 1} are discussed. Formulas for the integration of the radial part and the arising auxiliary integrals are deduced and convergence proofs are given. 7 refs., 4 figs.

The first nonrelativistic lower bound to the ground state of the lithium atom is give with E0 > −7.47816 au using the method of variance minimization and an extension of Temple's formula. With large Hylleraas–CI basis sets, high-precision upper bounds and isotope shifts are calculated for the three lowest 2S states of the lithium atom, which are best to date. © 1994 John Wiley & Sons, Inc.

In this paper, a general method is presented that allows the derivation of the expansion coefficients of the product of two orthogonal functions provided the generating function is known. For the three classical orthogonal polynomials, the Laguerre, the Hermite, and the Legendre polynomials, the coefficients blmn with ϕmϕn = ∑lblmnϕl are derived. © 1993 John Wiley & Sons, Inc.

Hylleraas–CI calculations with linked correlation terms of the form rr are discussed. Formulas for the integration of the angular part are deduced and a method for the reduction of the radial part to auxiliary integrals is given. In the case of the Li atom, it is shown that for the calculation of the ground-state energy an ansatz for the wave function with at most two factors rr is sufficient to achieve spectroscopic accuracy. © 1993 John Wiley & Sons, Inc.

A new expansion for r 12 -2 expressed in terms of Legendre polynomials is given. The explicit expression is... For the coefficients C' l,k and C l,k numerically stable formulas are derived