Diagrammatic perturbation theory: N_{2} X ^{1}Σ^{+}_{g}
Abstract
The diagrammatic manybody perturbation theory is used to calculate the correlation energy of the nitrogen molecule in its electronic ground state. Using the algebraic approximation, the energy is evaluated through third order, including all manybody effects. [2/1] Padé approximants and variational upper bounds are constructed. For one of the perturbation expansions considered, the [2/1] Padé approximant leads to the recovery of 79.5% of the empirical correlation energy, while the variational upper bound recovers 72.0%. Threebody effects are examined in some detail. The relationships with previous work on N_{2} are discussed.
 Publication:

Journal of Chemical Physics
 Pub Date:
 August 1977
 DOI:
 10.1063/1.435003
 Bibcode:
 1977JChPh..67.1689W
 Keywords:

 Correlation;
 Ground State;
 Hartree Approximation;
 Many Body Problem;
 Nitrogen;
 Perturbation Theory;
 Calculus Of Variations;
 Electron States;
 Hamiltonian Functions;
 Pade Approximation;
 Three Body Problem;
 Atomic and Molecular Physics;
 31.20.Tz