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Start Over Descriptor "correlation energy" Topic configuration interaction
36 results on '"correlation energy"'

1. Probing Collins Conjecture with correlation energies and entanglement entropies for the ground and excited states in the helium iso‐electronic sequence.

Author

Lin, Yen‐Chang and Ho, Yew Kam

Subjects
*QUANTUM entropy, *EXCITED states, *SELF-consistent field theory, *HELIUM, *LOGICAL prediction, *TOPOLOGICAL entropy, *VON Neumann algebras
Abstract

In the present work, we present an investigation of Collins Conjecture, a hypothesis made by D. M. Collins in 1993 relating correlation energy and entanglement entropy, by calculating the ground state and singly‐excited triplet‐spin 1s2s 3S and 1s3s 3S state energies of the helium iso‐electronic sequence, with Z = 2–15. By using extensive orthonormal configuration interaction (CI) type wave functions with B‐Spline basis up to about 6000 terms, linear entropy and von Neumann entropy for the abovementioned atomic systems are determined. Together with the Hartree‐Fock energies obtained following a self‐consistent field theory, we have found that there exist linearly proportionalities between the renormalized correlation energies and entanglement entropies of both linear and von Neumann, showing a support for Collins Conjecture applicable to the ground and singly‐excited triplet‐spin states in the helium sequence, for a range of finite Z‐values. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Correlation Energy Contributions from Low-lying States to Density Functionals in the KLI Approximation

Author

Gutle, C., Savin, A., Krieger, J. B., Maruani, Jean, editor, Minot, Christian, editor, McWeeny, Roy, editor, Smeyers, Yves G., editor, Wilson, Stephen, editor, Lipscomb, W.N., editor, Prigogine, I., editor, Ågren, H., editor, Avnir, D., editor, Cioslowski, J., editor, Daudel, R., editor, Gross, E.K.U., editor, Gunsteren, W.F.van, editor, Hirao, K., editor, Hubač, I., editor, Levy, M.P., editor, Malli, G.L., editor, Mezey, P.G., editor, Nascimento, M.A.C., editor, Rychlewski, J., editor, Schwartz, S.D., editor, Suhai, S., editor, Tapia, O., editor, Taylor, P.R., editor, and Woolley, R.G., editor

Published
2001
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3. Per-Olov Löwdin – father of quantum chemistry.

Author

Brändas, Erkki J.

Subjects
*CHEMISTS, *QUANTUM chemistry, *MOLECULAR structure, *PHYSICAL & theoretical chemistry
Abstract

During 2016, we celebrate the 100th anniversary of the birth of Per-Olov Löwdin. He was appointed to the first Lehrstuhl in quantum chemistry at Uppsala University in 1960. Löwdin introduced quantum chemistry as a field in its own right by formulating its goals, establishing fundamental concepts, like the correlation energy, the method of configuration interaction, reduced density matrices, natural spin orbitals, charge and bond order matrices, symmetric orthogonalisation, and generalised self-consistent fields. His exposition of partitioning technique and perturbation theory, wave and reaction operators and associated non-linear summation techniques, introduced mathematical rigour and deductive order in the interpretative organisation of the new field. He brought the first computer to Uppsala University and pioneered the initiation of ‘electronic brains’ and anticipated their significance for quantum chemistry. Perhaps his single most influential contribution to the field was his education of two generations of future faculty in quantum chemistry through Summer Schools in the Scandinavian Mountains, Winter Institutes at Sanibel Island in the Gulf of Mexico. Per-Olov Löwdin founded the book seriesAdvances in Quantum Chemistryand theInternational Journal of Quantum Chemistry. The evolution of quantum chemistry is appraised, starting from a collection of cross-disciplinary applications of quantum mechanics to the technologically advanced and predominant field of today, virtually used in all branches of chemistry. The scientific work of Per-Olov Löwdin has been crucial for the development of this new important province of science. [ABSTRACT FROM AUTHOR]

Published
2017
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6. Density functionals: Where do they come from, why do they work?

Author

Ernzerhof, Matthias, Perdew, John P., Burke, Kieron, Dunitz, Jack D., editor, Hafner, Klaus, editor, Houk, Kendall N., editor, Ito, Sho, editor, Lehn, Jean-Marie, editor, Raymond, Kenneth N., editor, Rees, Charles W., editor, Thiem, Joachim, editor, Vögtle, Fritz, editor, and Nalewajski, R. F., editor

Published
1996
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9. Coupled-cluster Methods in Quantum Chemistry

Author

Taylor, Peter R., Berthier, Gaston, editor, Dewar, Michael J. S., editor, Fischer, Hanns, editor, Fukui, Kenichi, editor, Hall, George G., editor, Hinze, Jürgen, editor, Jortner, Joshua, editor, Kutzelnigg, Werner, editor, Ruedenberg, Klaus, editor, Tomasi, Jacopo, editor, and Roos, Björn O., editor

Published
1994
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12. Introduction

Author

Fraga, Serafin, Klobukowski, M., Muszynska, J., Fabian, E. San, Saxena, K. M. S., Sordo, J. A., Sordo, T. L., Berthier, Gaston, editor, Dewar, Michael J. S., editor, Fischer, Hanns, editor, Fukui, Kenichi, editor, Hall, George G., editor, Hinze, Jürgen, editor, Jaffé, Hans, editor, Jortner, Joshua, editor, Kutzelnigg, Werner, editor, Ruedenberg, Klaus, editor, Tomasi, Jacopo, editor, Fraga, Serafin, Klobukowski, M., Muszynska, J., Fabian, E. San, Saxena, K. M. S., Sordo, J. A., and Sordo, T. L.

Published
1993
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22. Pair Correlation Theories

Author

Kutzelnigg, Werner, Miller, William H., editor, Schaefer, Henry F., III, editor, Berne, Bruce J., editor, and Segal, Gerald A., editor

Published
1977
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24. Potential Energy Hypersurface Calculations for Simple Systems

Author

Gianturco, Franco Antonio, Berthier, Gaston, editor, Dewar, Michael J. S., editor, Fischer, Hanns, editor, Fukui, Kenichi, editor, Hartmann, Hermann, editor, Jaffé, Hans H., editor, Jortner, Joshua, editor, Kutzelnigg, Werner, editor, Ruedenberg, Klaus, editor, Scrocco, Eolo, editor, Zeil, Werner, editor, and Gianturco, Franco Antonio

Published
1979
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