Unformatted text preview: Molecular Orbitals
part I Diatomic molecules: bonding proper8es Once energies (E) are known, we may determine wavefunc8ons (MO wavefunc8ons) The Born
Oppenheimer approxima8on • The Born
Oppenheimer (BO) approxima8ons consists in assuming that for a broad class of molecular and solid systems, the separa8on between nuclear and ionic mo8on is approximately correct. The approxima8on rests on the fact that the nuclei (with mass Mα) are much more massive than the electrons (with mass me ) and thus in most cases they are nearly ﬁxed with respect to electronic mo8on. Hence we can write: M. Born, R. Oppenheimer, Ann. Phys. (Leipzig) 84, 457 (1927). The Hartree
Fock approxima8on Approxima+on for the many
body electronic wavefunc+on which is expressed as an an+symmetrized product of N orthonormal single par+cle orbitals, each [email protected] as a product of a spa+al orbital and a Prof. D.R. spin func+on: Hartree, Cambridge, UK, 1897
1958 Prof. V.A.Fock, St.Petersburg, Russia 1898
1974 ...
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 Physical chemistry, Atom, Mole, pH, UK, Leipzig, approxima8on00 • The00

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