Title: zero differential overlap approximation
Long Title: IUPAC Gold Book - zero differential overlap approximation
DOI: 10.1351/goldbook.ZT07132
Status: current

Definition
An approach to the systematic neglect of the small-in-value electron repulsion integrals which is used in a number of approximate self-consistent field molecular orbital schemes. It means that all the products of atomic orbitals \(\upchi_{\upmu} \upchi_{\upnu}\) are set to zero and the overlap integral \(\rm{S}_{\upmu\upnu} = \updelta_{\upmu\upnu}\) (where \(\updelta_{\upmu\upnu}\) is the Kronecker delta). The ZDO approximation greatly simplifies the computation of wavefunctions by eliminating many of two-electron integrals. At the ZDO approximation all three- and four-centered integrals vanish.

Related Terms
- molecular orbital: https://goldbook.iupac.org//terms/view/M03996
- overlap integral: https://goldbook.iupac.org//terms/view/O04357

Source
- PAC, 1999, 71, 1919. 'Glossary of terms used in theoretical organic chemistry' on page 1970 (https://doi.org/10.1351/pac199971101919)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/ZT07132/html
- json: https://goldbook.iupac.org/terms/view/ZT07132/json
- xml: https://goldbook.iupac.org/terms/view/ZT07132/xml

Citation: Citation: 'zero differential overlap approximation' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.ZT07132
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Accessed: 2025-11-21T04:40:41+00:00