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Density-Matrix Functional Theory (DMFT)[Zumbach, Maschke, J.Chem. Phys. 82 (1985) 5604 and further developments]
Matrix g:In the literature, it is denoted also as G or r1) called also one-matrix, one-particle spinless reduced density matrix,or just « density matrix ».
DMFT, T. Wesolowski, University of Geneva, 2016
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Ho = T + Vee
Vext
Notation:
Admissible density matrices g:
set of matrices which are well-behaving in variational principle.Note the analogy with N-representability of electron density r1.
DMFT, T. Wesolowski, University of Geneva, 2016
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Density-Matrix Functional Theory (DMFT)[Zumbach, Maschke, J.Chem. Phys. 82 (1985) 5604 and further developments]
Levy-Lieb universal functional
(note the similarity to the constrained search definitio of the functional FHK[r])
DMFT, T. Wesolowski, University of Geneva, 2016
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Density-Matrix Functional Theory (DMFT)[Zumbach, Maschke, J.Chem. Phys. 82 (1985) 5604 and further developments]
Universal « Hohenberg-Kohn-like »functional in DMFT:
F[g] = T[g] + Vee[g] = T[g] + J[g] + Exc[g]
DMFT, T. Wesolowski, University of Geneva, 2016
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Or to avoid confusion with Exc[r]=T[r] - Ts[r] + Vee[r]- J[r]:
F[g] = T[g] + Vee[g] = T[g] + J[g] + Oxc[g]
Density-Matrix Functional Theory (DMFT)[Zumbach, Maschke, J.Chem. Phys. 82 (1985) 5604 and further developments]
Theorem:
where
DMFT, T. Wesolowski, University of Geneva, 2016
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g g
Density-Matrix Functional Theory (DMFT)[Zumbach, Maschke, J.Chem. Phys. 82 (1985) 5604 and further developments]
Variational principle
where,
The Lagrange multiplyier represents the constraint:
DMFT, T. Wesolowski, University of Geneva, 2016
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Or as derived by Zumbach and Maschkein the appendix [J. Chem. Phys. 82, (1985) 5694]
Density-Matrix Functional Theory (DMFT)[Zumbach, Maschke, J.Chem. Phys. 82 (1985) 5604 and further developments]
Euler-Lagrange Equation for g
Approximating the functional Exc[g]
Admissible density matrices g can be represented as:
g(r’,r) = S ni fi*(r’)fi(r)
E[g] can be represented as a functional depending on {ni} and {fi}.
E[g] = E[{ni},{fi}]
A typical approximation to the Exc[g] component of E[g] has the form:
DMFT, T. Wesolowski, University of Geneva, 2016
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Approximating the functional Exc[g] (1)
Müller, 1984:
Goeddeker & Umrigar, 1998:
Csányi&Arias, 2000:
Csányi, Goeddeker&Arias, 2002:
DMFT, T. Wesolowski, University of Geneva, 2016
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DMFT, T. Wesolowski, University of Geneva, 2016
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Piris, 2006:
Piris, 2006:
Approximating the functional Exc[g] (2)
DMFT, T. Wesolowski, University of Geneva, 2016
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Baerends and collaborators, 1991-2005:
Approximating the functional Exc[g] (3)
DMFT results (1)atomization energies with approximated Exc[g]
N.N. Lathiotakis, M.A.L. Marques, J. Chem. Phys. vol. 128 (2008) 184103.
DMFT, T. Wesolowski, University of Geneva, 2016
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DMFT results (2) correlation energies with approximated Exc[g]
N.N. Lathiotakis, M.A.L. Marques, J. Chem. Phys. vol. 128 (2008) 184103.
DMFT, T. Wesolowski, University of Geneva, 2016
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DMFT results (3) waekly occupied levels
N.N. Lathiotakis, M.A.L. Marques, J. Chem. Phys. vol. 128 (2008) 184103.
DMFT, T. Wesolowski, University of Geneva, 2016
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DMFT results (4) correlation energies with approximated Exc[g]
N.N. Lathiotakis, M.A.L. Marques, J. Chem. Phys. vol. 128 (2008) 184103.
DMFT, T. Wesolowski, University of Geneva, 2016
14
DMFT results (5) Benchmarking the Piris’ functional
Piris et al., . J. Chem. Phys. vol. 132 (2010) 031103
DMFT, T. Wesolowski, University of Geneva, 2016
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