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International Workshop on 'New challenges in Reduced Density Matrix Functional Theory: Symmetries, time-evolution and entanglement'

September 26, 2017 to September 29, 2017
Location : CECAM-HQ-EPFL, Lausanne, Switzerland
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Combining methods without double counting in RDMFT context

Andreas Savin
University Pierre and Marie Curie, France

Abstract

Ideas that were presented as seamlessly combining wave function methods with density functionals can be seen from a reduced density matrix perspective:
• some derivations appear natural in this context,
• the wave function part can be replaced by a reduced density matrix part [1].
The usage of density functionals can be motivated by the slow convergence of the kinetic energy with basis set size, due to the singularity in the Coulomb potential [2]. Two strategies are discussed: (a) using natural orbitals [3, 4] and (b) using orbital spaces [5, 6]. Furthermore, the adiabatic connection can be reformulated, and applied from different perspectives:
• for computing the correlation energy using the kinetic energy evolution [7, 8, 9],
• by using extrapolation [10, 11, 12].



References

[1] D. R. Rohr, J. Toulouse, K. Pernal, Phys. Rev. A 82 052502 (2010).
[2] J. C. Kimball J. Phys. A : Math. Gen. 8 1513 (1975).
[3] A. Savin, Int. J. Quantum Chem. S22, 59 (1988).
[4] A. Savin, in: J.K. Labanowski, J.W. Andzelm, eds., Density functional methods in chemistry, Springer-Verlag, New York (1991), p. 213.
[5] J. Rey, A. Savin, Int. J. Quantum Chemistry 69 581 (1998).
[6] C. Gutlé, A. Savin, Phys. Rev. A 75 032519 (2007).
[7] A. Savin, Phys. Rev. A 52 R1805 (1995).
[8] M. Levy, A. Görling, A. Phys. Rev. A 52 R1808 (1995).
[9] A. M. Teale, T. Helgaker, A. Savin J. Chin. Chem. Soc. 63 121 (2016).
[10] P. Y. Ayala, G. E. Scuseria, A. Savin, Chem. Phys. Lett. 307 227 (1999).
[11] S. Iyengar, G. Scuseria, A. Savin, Int. J. Quantum Chemistry 79 222 (2000).
[12] A. Savin, J. Chem. Phys. 134 214108 (2011).