VARIATIONAL ANSATZ FOR EFFECTIVE-HAMILTONIANS - SOLUTION OF CONVERGENCE PROBLEM VIA THE INTERMEDIATE HAMILTONIAN APPROACHстатья
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Дата последнего поиска статьи во внешних источниках: 3 октября 2014 г.
Аннотация:The variational intermediate Hamiltonian approach is developed on the basis of the quasi-Rayleigh-Schrodinger quasi-degenerate perturbation theory. The results of test applications to ab initio calculations of molecular excited states are discussed. The new approach is able to produce rapidly and monotonically convergent sequences of energy estimates while the ordinary variational effective Hamiltonian method suffers from catastrophic divergencies in the presence of intruder states.