Molecular electron propagators

Y. Ohrn, G. Bom, Molecular electron propagator theory and calculations. Adv. Quantum Chem. 13, 1-88 (1981)... 

Ortiz J V 1997 The electron propagator picture of molecular electronic structure Computational Chemistry Reviews of Current Trends vo 2, ed J Leszczynski (Singapore World Scientific) pp 1-61... 

Hartree-Fock (HF), molecular orbital theory satisfies most of the criteria, but qualitative failures and quantitative discrepancies with experiment often render it useless. Methods that systematically account for electron correlation, employed in pursuit of more accurate predictions, often lack a consistent, interpretive apparatus. Among these methods, electron propagator theory [1] is distinguished by its retention of many conceptual advantages that facilitate interpretation of molecular structure and spectra [2, 3, 4, 5, 6, 7, 8, 9]. 

Electron propagator theory generates a one-electron picture of electronic structure that includes electron correlation. One-electron energies may be obtained reliably for closed-shell molecules with the P3 method and more complex correlation effects can be treated with renormalized reference states and orbitals. To each electron binding energy, there corresponds a Dyson orbital that is a correlated generalization of a canonical molecular orbital. Electron propagator theory enables interpretation of precise ab initio calculations in terms of one-electron concepts. 

The complete Hamiltonian of the molecular system can be wrihen as H +H or H =H +H for the commutator being linear, where is the Hamiltonian corresponding to the spin contribution(s) such as, Fermi contact term, dipolar term, spin-orbit coupling, etc. (5). As a result, H ° would correspond to the spin free part of the Hamiltonian, which is usually employed in the electron propagator implementation. Accordingly, the k -th pole associated with the complete Hamiltonian H is , so that El is the A -th pole of the electron propagator for the spin free Hamiltonian H . 

If the Kohn-Sham orbitals [52] of density functional theory (DFT) [53] are used instead of Hartree-Fock orbitals in the reference state [54], the RI can become essential for the realization of electron propagator calculations. Modern implementations of Kohn-Sham DFT [55] use the variational approximation of the Coulomb potential [45,46] (which is mathematically equivalent to the RI as presented above), and four-index integrals are not used at all. A very interesting example of this combination is the use of the GW approximation [56] for molecular systems [54],... 

The applications of nonequilibrium Green s functions to the calculations of different molecular devices show the importance of electron correlation effects. The electron propagator method is able to explain experimental data and predict new electronic devices. 

Yu. Dahnovsky, V.G. Zakrzewski, A. Kletsov, J.V. Ortiz, Ab Initio electron propagator theory of molecular wires I. Formalism, J. Chem. Phys. 123 (2005) 184711. 

M.R. Sterling, O. Dolgunitcheva, V.G. Zakrzewski, Yu. Dahnovsky, J.V. Ortiz, Correlated, ab initio electron propagators in the study of molecular wires Application to a single molecular bridge placed between two model leads, Intern. J. Quant. Chem. 107 (2007) 3228. 

W.D. Wheeler, Yu. Dahnovsky, Quantum interference in molecular wires Electron propagator calculations, J. Phys. Chem. C 112 (2008) 13769-13774. 

Since the complex scaling of the exponents of the primitive basis set will lead to a complex primitive basic set u and hence to the loss of biorthogonality central to our constructions, the Moiseyev-Corcoran approach has been adopted by us /44-46/ and Donnelly /21,47-50/ in the construction of the molecular dilated electron propagator. 

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