IUPAC > Gold Book > alphabetical index > N > natural population analysis (NPA)


natural population analysis (NPA)

The analysis of the electron density distribution in a molecular system based on the orthonormal natural atomic orbitals. Natural populations, n i A are the occupancies of the natural atomic orbitals. These rigorously satisfy the Pauli exclusion principle: 0 < n i A < 2. The population of an atom n A is the sum of natural populations n A = ∑ A n i A. A distinguished feature of the NPA method is that it largely resolves the basis set dependence problem encountered in the Mulliken population analysis method.
PAC, 1999, 71, 1919 (Glossary of terms used in theoretical organic chemistry) on page 1954
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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. doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.NT07080.
Original PDF version: http://www.iupac.org/goldbook/NT07080.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.
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