Natural bond orbital-based energy density analysis (NBO-EDA), which split energies into atomic and bonding contributions, is proposed for correlated methods such as coupled-cluster singles and doubles (CCSD) and second-order Møller-Plesset (MP2) perturbation. Applying NBO-EDA for CCSD and MP2 to ethylene and the Diels-Alder reaction, we are successful in obtaining useful knowledge regarding electron correlation of π- and σ-type orbitals, and clarifying the difference of the reaction barriers and heat of reaction calculated by CCSD and MP2.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Physical and Theoretical Chemistry