Size consistent multireference single and double excitation configuration interaction calculations. The multireference coupled electron‐pair approximation

A new size consistent extension to the multi reference configuration interaction method is described. The method termed multireference coupled electron pair approximation (MRCEPA) is akin to a multireference CEPA(0) approach, though nonlinear terms do receive separate attention. We show the performance of the approach in some model systems as well as in an application to calculation of ground and excited ππ* states of ethylene.

[1]  Edward Teller,et al.  Electronic Spectra of Polyatomic Molecules , 1941 .

[2]  S. Huzinaga.  Variational Calculation of Ethylene , 1962 .

[3]  H. P. Kelly.  CORRELATION EFFECTS IN MANY FERMION SYSTEMS: MULTIPLE PARTICLE EXCITATION EXPANSION - eScholarship , 1963 .

[4]  H. P. Kelly.  CORRELATION EFFECTS IN MANY FERMION SYSTEMS. II. LINKED CLUSTERS , 1964 .

[5]  K. Kuchitsu.  Calculation of the Average Structure of Ethylene , 1966 .

[6]  Bernard Levy,et al.  Generalized brillouin theorem for multiconfigurational SCF theories , 1968 .

[7]  T. Dunning,et al.  The theoretical description of the (*) excited states of ethylene, , 1969 .

[8]  J. Cizek,et al.  Cluster expansion analysis for delocalized systems , 1969 .

[9]  Wilfried Meyer,et al.  PNO–CI Studies of electron correlation effects. I. Configuration expansion by means of nonorthogonal orbitals, and application to the ground state and ionized states of methane , 1973 .

[10]  Ernest R. Davidson,et al.  Configuration interaction calculations on the nitrogen molecule , 1974 .

[11]  V. R. Saunders,et al.  On methods for converging open-shell Hartree-Fock wave-functions , 1974 .

[12]  Pavel Rosmus,et al.  PNO–CI and CEPA studies of electron correlation effects. III. Spectroscopic constants and dipole moment functions for the ground states of the first‐row and second‐row diatomic hydrides , 1975 .

[13]  A. C. Hurley.  Electron correlation in small molecules , 1976 .

[14]  B. Straughan,et al.  Electronic Spectra of Polyatomic Molecules , 1976 .

[15]  E. Davidson,et al.  Configuration interaction calculations on the planar 1(π,π*) state of ethylene , 1977 .

[16]  H. Schaefer.  Methods of Electronic Structure Theory , 1977 .

[17]  B. Brooks,et al.  N (1Ag), T (3B1u), and V (1B1u) states of vertical ethylene , 1978 .

[18]  R. Ahlrichs,et al.  Many body perturbation calculations and coupled electron pair models , 1979 .

[19]  Josef Paldus,et al.  Applicability of coupled‐pair theories to quasidegenerate electronic states: A model study , 1980 .

[20]  W. Kutzelnigg,et al.  Comparison of CEPA and CP-MET methods , 1980 .

[21]  P. Wormer,et al.  Relationship between configuration interaction and coupled cluster approaches , 1982 .

[22]  Ajit Banerjee,et al.  The coupled‐cluster method with a multiconfiguration reference state , 1981 .

[23]  Peter R. Taylor,et al.  The choice of Gaussian basis sets for molecular electronic structure calculations , 1981 .

[24]  H. Monkhorst,et al.  Coupled-cluster method for multideterminantal reference states , 1981 .

[25]  S. Peyerimhoff,et al.  Nonadiabatic treatment of the intensity distribution in the V–N bands of ethylene , 1982 .

[26]  Ajit Banerjee,et al.  Applications of multiconfigurational coupled‐cluster theory , 1982 .

[27]  Ron Shepard,et al.  C2V Insertion pathway for BeH2: A test problem for the coupled‐cluster single and double excitation model , 1983 .

[28]  M. Robb,et al.  A size consistent unitary group approach Multi-reference linear coupled cluster theory , 1983 .

[29]  Rodney J. Bartlett,et al.  A multi-reference coupled-cluster method for molecular applications , 1984 .

[30]  Kiyoshi Tanaka,et al.  A cluster expansion theory with multireference functions using the unitary ansatz , 1984 .

[31]  P. Knowles,et al.  An efficient second-order MC SCF method for long configuration expansions , 1985 .

[32]  M. Gutowski,et al.  THE BASIS SET SUPERPOSITION ERROR IN CORRELATED ELECTRONIC STRUCTURE CALCULATIONS , 1986 .

[33]  J. V. Lenthe,et al.  On the existence of trans-cyclohexene , 1987 .

[34]  Robert J. Harrison,et al.  Computational chemistry on the FPS-X64 scientific computers , 1987 .

[35]  Ernest R. Davidson,et al.  Hylleraas variational perturbation theory: Application to correlation problems in molecular systems , 1988 .

[36]  P. Knowles,et al.  An efficient internally contracted multiconfiguration–reference configuration interaction method , 1988 .

[37]  Ernest R. Davidson,et al.  Quasidegenerate Variational Perturbation Theory and the Calculation of First‐Order Properties from Variational Perturbation Theory Wave Functions , 1988 .

[38]  Robert J. Gdanitz,et al.  The averaged coupled-pair functional (ACPF): A size-extensive modification of MR CI(SD) , 1988 .

[39]  S. Langhoff,et al.  The effect of higher than double excitations on the F+H2→FH+H barrier , 1989 .

[40]  R. J. Cave.  Size‐inconsistency effects in molecular properties for states with valence‐Rydberg mixing: The low‐lying π→π* states of ethylene and butadiene , 1990 .