-shell atomic orbital whose derivation involves diagonalising the localized block
of the full density matrix of a given molecule associated with basis functions
on that atom. A distinguishing feature of NAO
s is that they meet the simultaneous requirement of orthonormality and maximum occupancy.
For isolated atoms, NAO
s coincide with natural orbitals. In a polyatomic molecule the NAO
s (in contrast to natural orbitals that become delocalised over all nuclear centres)
mostly retain one-centre character, and thus are optimal for describing the molecular
around each atomic centre.
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook