Abstract

Abstract The definition of a molecular property as a derivative of the electronic energy with respect to one or more applied perturbations is reviewed. The explicit enumeration of terms entering the derivative formulas is performed by considering in turn the various parameter spaces on which the energy and wave function depend. After deriving general expressions for first, second, and third derivatives for different types of perturbation, the parameter spaces involved in MCSCF and CI cases are identified and used to obtain expressions for the first and second derivatives. An example of an MCSCF third derivative is also given. In addition, the various equation systems defining the perturbed wave functions in each order are derived. Some attention is given to the efficient computer implementation of derivative calculations, and the present work is compared with that of other authors.

Keywords

Wave functionPerturbation (astronomy)Perturbation theory (quantum mechanics)Functional derivativeDerivative (finance)Second derivativeComputational chemistryThird orderApplied mathematicsFunction (biology)MathematicsChemistryMathematical analysisPhysicsQuantum mechanics

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Publication Info

Year
1985
Type
article
Volume
27
Issue
6
Pages
743-768
Citations
71
Access
Closed

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Jan Almløf, Peter R. Taylor (1985). Molecular properties from perturbation theory: A Unified treatment of energy derivatives. International Journal of Quantum Chemistry , 27 (6) , 743-768. https://doi.org/10.1002/qua.560270610

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DOI
10.1002/qua.560270610