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Brillouin-Wigner perturbation theory application

Today, there remain a number of problems in molecular electronic structure theory. The most outstanding of these is undoubtedly the development of a robust theoretical apparatus for the accurate description of dissociative processes which usually demand the use of multi-reference functions. This requirement has recently kindled a renewal of interest in the Brillouin-Wigner perturbation theory and its application to such problems. This contribution describes the application of... [Pg.39]

On the application of Brillouin- Wigner perturbation theory to a relativistic and non-relativistic hydrogenio model problem... [Pg.62]

The above extracts serve to demonstrate what had until recently been the standard view of Brillouin-Wigner perturbation theory and its applicability to many-body systems. [Pg.26]

In this chapter, we come to the central purpose of this volume - the application of Brillouin-Wigner methods to many-body atomic and molecular systems. We have seen in Chapter 2 that Brillouin-Wigner perturbation theory [2-4] leads to energy expressions with denominators which contain the exact energy, . As a consequence of this, the Brillouin-Wigner expansion yields energy components which scale non-linearly with the number of electrons in the system. The method does not have. [Pg.133]

If j) is a determinant related to one of the reference determinants by a double replacement, then k) involves, at most, quadruple replacements with respect to 1 ) in eq. (4.193). Repeated application of the Lippmann-Schwinger-file equation [160] leads to higher order replacements. If we restrict the degree of replacement admitted in (4.193) then we realize a limited multi-reference configuration interaction method. It is this realization of the multi-reference limited configuration interaction method that we use to obtain an a posteriori correction based on Brillouin-Wigner perturbation theory. [Pg.175]

In the context of the Wigner-Seitz theory, in 1937 Brillouin [7] gave a formal analysis of the atomic energy variations under boundary deformations using contact coordinate transformations that transform the boundary modifications into Hamiltonian transformations for a fixed region and generate the associated commutation relations. This allows application of the usual form of perturbation theory for the problem. [Pg.27]

We shall provide an overview of the applications that have been made over the period being review which demonstrate the many-body Brillouin-Wigner approach for each of these methods. By using Brillouin-Wigner methods, any problems associated with intruder states can be avoided. A posteriori corrections can be introduced to remove terms which scale in a non linear fashion with particle number. We shall not, for example, consider in any detail hybrid methods such as the widely used ccsd(t) which employs ccsd theory together with a perturbative estimate of the triple excitation component of the correlation energy. [Pg.57]

Many-body Brillouin- Wigner second-order perturbation theory an application to the autoaromatisation of hex-3-ene-1,5-dlyne (the Bergman reaction)... [Pg.60]

Many-body Brillouin-Wigner second-order perturbation theory using a multireference formulation an application to bond breaking in the diatomic hydrides BH and FH Molecular Physics 104, 2367 (2006)... [Pg.60]


See other pages where Brillouin-Wigner perturbation theory application is mentioned: [Pg.466]    [Pg.53]    [Pg.71]    [Pg.72]    [Pg.76]    [Pg.5]    [Pg.23]    [Pg.32]    [Pg.53]    [Pg.178]    [Pg.184]    [Pg.192]    [Pg.196]    [Pg.259]    [Pg.344]    [Pg.467]    [Pg.181]    [Pg.592]    [Pg.1706]    [Pg.26]    [Pg.33]    [Pg.76]    [Pg.244]    [Pg.244]   
See also in sourсe #XX -- [ Pg.77 ]




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