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Brillouin-Wigner

In the Brillouin-Wigner perturbation formalism, the following identity is used... [Pg.242]

Here we ignore any possible perturbation to the site energies at the ends of the chain, n = 1 and n = m.) We apply Brillouin-Wigner perturbation theory (Ohanian 1990), whereby the eigenvalue of a non-degenerate state can be expressed as... [Pg.120]

Multireference Brillouin-Wigner Coupled-Cluster Theory. [Pg.75]

Within the multireference BWPT [45], the exact wave functions for o = 1,..., d can be expanded in the Brillouin-Wigner (BW) perturbation series as follows... [Pg.79]

So far, we have specified the wave operator H in the BW form (15). If we adopt an exponential ansatz for the wave operator Cl, we can speak about the single-root multireference Brillouin-Wigner coupled-cluster (MR BWCC) theory. The simplest way how to accomplish the idea of an exponential expansion is to exploit the so-called state universal or Hilbert space exponential ansatz of Jeziorski and Monkhorst [23]... [Pg.83]

I. Hubac, Size Extensive Brillouin-Wigner Coupled-Cluster Theory. In A. Tsipis, V. S. Popov, D. R. Herschbach, and J. S. Avery (Eds.) New Methods in Quantum... [Pg.42]

Eq. (3.12) represents the Brillouin-Wigner (BW) perturbation expansion of the exact wave function, whereas the corresponding expression for the... [Pg.19]

Lennard-Jones Brillouin Wigner Perturbation Theory.—Let us write the total hamiltonian operator as a sum of a zero-order operator and a perturbation... [Pg.5]

In Lennard-Jones Brillouin Wigner perturbation theory the wave operator is written as... [Pg.6]

Explicitly, the first few terms in the Lennard-Jones Brillouin Wigner perturbation series take the form... [Pg.6]

The Lennard-Jones Brillouin Wigner perturbation expansion is a simple geometric series. However, it contains the unknown exact energy within the denominators. This expansion is, therefore, not a simple power series in the perturbation. [Pg.6]


See other pages where Brillouin-Wigner is mentioned: [Pg.75]    [Pg.77]    [Pg.80]    [Pg.93]    [Pg.93]    [Pg.24]    [Pg.38]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.19]    [Pg.21]    [Pg.23]    [Pg.87]    [Pg.149]    [Pg.150]    [Pg.155]    [Pg.77]    [Pg.309]   
See also in sourсe #XX -- [ Pg.35 ]

See also in sourсe #XX -- [ Pg.38 , Pg.40 , Pg.44 , Pg.45 , Pg.46 , Pg.47 , Pg.48 , Pg.49 , Pg.50 , Pg.57 , Pg.64 ]




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