Quantum field theoretical methods in chemically bonded systems. V. Potential energy curves for N2(X1Σmath image) → 2N (4S)


  • This work was supported in part by IBM RSP 3112 and in part by the U.S. Department of the Navy, Space and Naval Warfare Systems Command under Contract N00039-89-C-0001. It was presented, in part, at the Midwest Theoretical Chemistry Conference, Eastc Lansing, Michigan, May 1992.


Many-body perturbation theory is applied to the nitrogen triple bond for bond distances ranging from the atomic regime to about 0.6a0 shorter than equilibrium. A full-optimized reaction space model is used to compute orbital spaces with an even-tempered gaussian-type basis set and also with a nominal Bagus–Gilbert Slater-type basis set. Conservation of orbital angular momentum in the atomic regime leads to perturbative theory for Hartree–Fock plus proper dissociation. Angular momentum conservation can also be enforced with a scaled Slater–Condon parameter. Third-order dissociation energies and spectroscopic constants approach limits of the chosen basis sets. © 1993 John Wiley & Sons, Inc.