Applications of density functional theory approaching chemical accuracy to the study of typical carbon-carbon and carbon-hydrogen bonds

摘要

This article examines the merits of cost-efficient density functional variants in the computation of prototype hydrocarbons; CH4, C2Hc, C2H4, C2Hi, benzene and cyclopropane. Inclusion of some Hartree-Fock exchange in a fully self-consistent density functionalapproach with gradient corrections leads to atomization energies close to experimental accuracy. Validation of Politzer's energy formula, E~(molecule)=E_KV_k~(mol)/r_k~(mol), where V_k~(mol) is the potential energy involving the nucleus of atom it in the molecule and R_k~(mol) is a parameter (-7/3 for atoms other than H), with better than Hartree-Fock wave functions provides a useful link with classical chemical concepts, namely bond energies.