Fock-space coupled-cluster method in the intermediate Hamiltonian formulation: Model with singles and doubles

1998 ◽  
Vol 108 (22) ◽  
pp. 9227-9235 ◽  
Author(s):  
Leszek Meissner
2005 ◽  
Vol 70 (6) ◽  
pp. 811-825 ◽  
Author(s):  
Monika Musiał ◽  
Leszek Meissner

Our recently developed intermediate Hamiltonian Fock-space coupled-cluster (FS-CC) method with singles and doubles is applied to calculation of equilibrium geometries, harmonic frequencies and adiabatic excitation energies for some excited states of N2 and CO. Due to the intermediate Hamiltonian formulation, which provides a robust computational scheme for solving the FS-CC equations, and the efficient factorization strategy, relatively large basis sets and reference spaces are employed permitting a comparison of calculated properties with experimental data.


2003 ◽  
Vol 68 (1) ◽  
pp. 105-138 ◽  
Author(s):  
Leszek Meissner ◽  
JarosłaW Gryniaków

Various aspects of the effective Hamiltonian and intermediate Hamiltonian formulations are discussed in the context of the Fock-space coupled-cluster method. Problems that occur when single-reference methods of solving the Schrödinger equation need to be generalized to the multireference (MR) cases are pointed out. These problems make the generalization nontrivial, especially in the case of the most powerful coupled-cluster (CC) method. It is shown how some specific features of one of the basic MR-CC schemes, the Fock-space CC method, can be used to obtain a simple, yet very effective version of the method. This requires, however, switching from the effective Hamiltonian to the intermediate Hamiltonian formulation. The intermediate Hamiltonian version of the Fock-space CC method is discussed in detail and all its advantages over the standard one are emphasized.


1985 ◽  
Vol 32 (2) ◽  
pp. 743-747 ◽  
Author(s):  
Leszek Z. Stolarczyk ◽  
Hendrik J. Monkhorst

1992 ◽  
Vol 194 (1-2) ◽  
pp. 99-104 ◽  
Author(s):  
S.R. Hughes ◽  
Uzi Kaldor

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