ISSN:
0020-7608
Keywords:
linear response
;
quadratic response
;
perturbation theory
;
electronic correlation
;
Green's function
;
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The equations satisfied by the first-order perturbed electron propagator in an applied external field are examined at a level equivalent to the two-particle-hole Tamm-Dancoff and extended two-particle-hole Tamm-Dancoff approximations (2ph-TDA). These schemes are derived with the intention of evaluating linear and quadratic response properties through second and third order in correlation. Their derivation is based on a combination of the diagrammatic and algebraic superoperator methods. Both schemes account for the polarization of the 2p-1h and 2h-1p responses and bielectron interactions under an external field. The 2ph-TDA scheme is correct up to second order in electronic correlation and includes infinite geometric series of mixed RPA-ladder-type character. Its extended version is derived consistently through third order and accounts for a first-order screening of the external field and bielectron interaction by the effects of electronic correlation. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 483-509, 1997
Additional Material:
15 Ill.
Type of Medium:
Electronic Resource
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