A parallel vectorized implementation of triple excitations in CCSD(T): application to the binding energies of the AlH3, AlH2F, AlHF2 and AlF3 dimers

Abstract An efficient method for evaluating various non-iterative estimates of connected triple excitations in coupled-cluster theory is outlined and related to a similar expression occurring in Moller-Plesset perturbation theory. The method is highly vectorized and capable of utilizing multiple processors on a shared-memory machine, leading to computational rates in excess of one billion floating-point operations per second on four processors of a CRAY Y-MP. Using the new procedure, the binding energies of the D 2h diborane-type dimers of AlH 3 , AlH 2 F, AlHF 2 and AlF 3 have been determined to be 32, 40, 20 and 47 kcal/mol, respectively. For Al 2 F 6 , the correlation procedure includes 232 molecular orbitals and over 1.5 × 10 6 single and double coupled-cluster amplitudes, effectively accounting for over 2 × 10 9 connected triple excitations.

[1]  R. Bartlett,et al.  The full CCSDT model for molecular electronic structure , 1987 .

[2]  L. Curtiss,et al.  Theoretical study of B2H+5, B2H+6, and B2H6 , 1988 .

[3]  K. Schaumburg,et al.  A Gas Phase Electron Diffraction Investigation of the Molecular Structures of Trimethylaluminium Monomer and Dimer. , 1971 .

[4]  G. Nivellini,et al.  The empirical harmonic potential function of diborane , 1983 .

[5]  M. Head‐Gordon,et al.  Fifth order Moeller-Plesset perturbation theory: comparison of existing correlation methods and implementation of new methods correct to fifth order , 1990 .

[6]  Peter R. Taylor,et al.  General contraction of Gaussian basis sets. I. Atomic natural orbitals for first‐ and second‐row atoms , 1987 .

[7]  Gustavo E. Scuseria,et al.  The vibrational frequencies of ozone , 1990 .

[8]  M. W. Chase.  JANAF thermochemical tables , 1986 .

[9]  H. Partridge.  Near Hartree–Fock quality GTO basis sets for the second‐row atoms , 1987 .

[10]  Josef Paldus,et al.  Correlation problems in atomic and molecular systems III. Rederivation of the coupled-pair many-electron theory using the traditional quantum chemical methodst†‡§ , 1971 .

[11]  Curtis L. Janssen,et al.  An efficient reformulation of the closed‐shell coupled cluster single and double excitation (CCSD) equations , 1988 .

[12]  Alistair P. Rendell,et al.  Comparison of the quadratic configuration interaction and coupled cluster approaches to electron correlation including the effect of triple excitations , 1990 .

[13]  S. F. Boys,et al.  The calculation of small molecular interactions by the differences of separate total energies. Some procedures with reduced errors , 1970 .

[14]  Henry F. Schaefer,et al.  A new implementation of the full CCSDT model for molecular electronic structure , 1988 .

[15]  G. Scuseria,et al.  Comparison of coupled-cluster methods which include the effects of connected triple excitations , 1990 .

[16]  Rodney J. Bartlett,et al.  Fifth-Order Many-Body Perturbation Theory and Its Relationship to Various Coupled-Cluster Approaches* , 1986 .

[17]  A. D. McLean,et al.  Contracted Gaussian basis sets for molecular calculations. I. Second row atoms, Z=11–18 , 1980 .

[18]  K. Lammertsma,et al.  Ab initio study on dialane(6) and digallane(6) , 1990 .

[19]  H. Schaefer,et al.  Theoretical investigations of molecules composed only of fluorine, oxygen and nitrogen: determination of the equilibrium structures of FOOF, (NO)2 and FNNF and the transition state structure for FNNF cis-trans isomerization , 1989 .

[20]  R. Bartlett.  Coupled-cluster approach to molecular structure and spectra: a step toward predictive quantum chemistry , 1989 .

[21]  R. Bartlett.  Many-Body Perturbation Theory and Coupled Cluster Theory for Electron Correlation in Molecules , 1981 .

[22]  S. J. Cole,et al.  Towards a full CCSDT model for electron correlation , 1985 .

[23]  Julia E. Rice,et al.  An efficient closed-shell singles and doubles coupled-cluster method , 1988 .

[24]  M. Head‐Gordon,et al.  A fifth-order perturbation comparison of electron correlation theories , 1989 .

[25]  A. J. Downs,et al.  Gallane at last! Synthesis and properties of binary gallium hydride , 1989 .

[26]  H. Schaefer,et al.  Infrared spectra of the unknown dialane (Al2H6) and recently observed digallane (Ga2H6) molecules , 1989 .

[27]  R. Ahlrichs,et al.  The impact of higher polarization basis functions on molecular ab initio results. I. The ground state of F2 , 1985 .

[28]  John D. Watts,et al.  Non-iterative fifth-order triple and quadruple excitation energy corrections in correlated methods , 1990 .

[29]  Alistair P. Rendell,et al.  Theoretical investigations of the structures and binding energies of Ben and Mgn(n=3–5) clusters , 1990 .