Ž .With large Hylleraas᎐configuration interaction CI basis sets highly accurate upper bounds for the lowest 2 P o states of the Li isoelectronic series up to Ne are given. The corresponding Hamiltonian H and the operator Ý ٌٌ are transformed into i-j i j nonorthogonal coordinates expressed in interparticle and angular terms. The evaluation of the occurring integrals is reduced to the calculation of well-known auxiliary integrals. Furthermore some expectation values and isotope energies are calculated. The isotope energies are obtained using perturbation theory in first-order approximation.
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