Auxiliary-field quantum Monte Carlo calculations of molecular systems with a Gaussian basis

Al-Saidi, W. A.; Shiwei Zhang; Krakauer, Henry
June 2006
Journal of Chemical Physics;6/14/2006, Vol. 124 Issue 22, p224101
Academic Journal
We extend the recently introduced phaseless auxiliary-field quantum Monte Carlo (QMC) approach to any single-particle basis and apply it to molecular systems with Gaussian basis sets. QMC methods in general scale favorably with the system size as a low power. A QMC approach with auxiliary fields, in principle, allows an exact solution of the Schrödinger equation in the chosen basis. However, the well-known sign/phase problem causes the statistical noise to increase exponentially. The phaseless method controls this problem by constraining the paths in the auxiliary-field path integrals with an approximate phase condition that depends on a trial wave function. In the present calculations, the trial wave function is a single Slater determinant from a Hartree-Fock calculation. The calculated all-electron total energies show typical systematic errors of no more than a few millihartrees compared to exact results. At equilibrium geometries in the molecules we studied, this accuracy is roughly comparable to that of coupled cluster with single and double excitations and with noniterative triples [CCSD(T)]. For stretched bonds in H2O, our method exhibits a better overall accuracy and a more uniform behavior than CCSD(T).


Related Articles

  • Unitary quantum time evolution by iterative Lanczos reduction. Park, Tae Jun; Light, J. C. // Journal of Chemical Physics;11/15/1986, Vol. 85 Issue 10, p5870 

    A general unitary time evolution method for wave packets defined on a fixed L2 basis is developed. It is based on the Lanczos reduction of the full N×N Hamiltonian to a p-dimensional subspace defined by the application of H p-1 times to the initial vector. Unitary time evolution in the...

  • An explicitly correlated coupled cluster calculation of the helium–helium interatomic potential. Klopper, Wim; Noga, Jozef // Journal of Chemical Physics;10/8/1995, Vol. 103 Issue 14, p6127 

    Explicitly correlated coupled cluster (CCSDT-1a-R12) results were obtained for the He2 interatomic potential from a new, integral-direct implementation. With the new code, Gaussian basis sets as large as 11s8p6d5f4g3h could be employed, and the potential energy curve was calculated over a wide...

  • Relativistic Quadruple-Zeta and Revised Triple-Zeta and Double-Zeta Basis Sets for the 4p, 5p, and 6p Elements. Dyall, Kenneth // Theoretical Chemistry Accounts: Theory, Computation, & Modeling;May2006, Vol. 115 Issue 5, p441 

    Relativistic basis sets of quadruple-zeta quality have been optimized at the self-consistent field (SCF) level with a Gaussian nuclear charge distribution for the 4p, 5p and 6p elements. To these sets, a valence correlating 3d2f1g set was optimized in multireference CI calculations on the...

  • Quantum flux operators and thermal rate constant: Collinear H+H2. Park, Tae Jun; Light, J. C. // Journal of Chemical Physics;4/15/1988, Vol. 88 Issue 8, p4897 

    The exact quantum formulation of the thermal rate constant, k(T), given by Miller et al. [W. H. Miller, J. Chem. Phys. 61, 1823 (1974); W. H. Miller, S. D. Schwartz, and J. W. Tromp, ibid. 79, 4889 (1983)] is evaluated in a localized [ATOTHER]@sL[/ATOTHER] 2 basis (distributed Gaussian basis)...

  • Relativistic Gaussian basis sets for molecular calculations: Cs–Hg. Koga, Toshikatsu; Tatewaki, Hiroshi; Matsuoka, Osamu // Journal of Chemical Physics;10/22/2002, Vol. 117 Issue 16, p7813 

    Relativistic Gaussian basis sets suitable for molecular calculations are presented for the 26 atoms [sub 55]Cs through [sub 80]Hg. This is the second part of our systematic generation of the basis sets, proposed in a previous paper [J. Chem. Phys. 115, 3561 (2001)]. For the 26 atoms, the maximum...

  • Functional regression modeling via regularized Gaussian basis expansions. Araki, Yuko; Konishi, Sadanori; Kawano, Shuichi; Matsui, Hidetoshi // Annals of the Institute of Statistical Mathematics;Dec2009, Vol. 61 Issue 4, p811 

    We consider the problem of constructing functional regression models for scalar responses and functional predictors, using Gaussian basis functions along with the technique of regularization. An advantage of our regularized Gaussian basis expansions to functional data analysis is that it creates...

  • A study of H+H2 and several H-bonded molecules by phaseless auxiliary-field quantum Monte Carlo with plane wave and Gaussian basis sets. Al-Saidi, W. A.; Krakauer, Henry; Zhang, Shiwei // Journal of Chemical Physics;5/21/2007, Vol. 126 Issue 19, p194105 

    The authors present phaseless auxiliary-field (AF) quantum Monte Carlo (QMC) calculations of the ground states of some hydrogen-bonded systems. These systems were selected to test and benchmark different aspects of the new phaseless AF QMC method. They include the transition state of H+H2 near...

  • Exact-exchange density functional theory for hyperpolarizabilities. Bokhan, Denis; Bartlett, Rodney J. // Journal of Chemical Physics;11/7/2007, Vol. 127 Issue 17, p174102 

    Time-dependent density functional theory (TDDFT) employing the exact-exchange functional (TDDFTx) has been formulated using the optimized effective potential method for the β static hyperpolarizabilities, where it reduces to coupled-perturbed Kohn-Sham theory. A diagrammatic technique is used...

  • Relativistic double-zeta, triple-zeta, and quadruple-zeta basis sets for the actinides Ac—Lr. Dyall, Kenneth // Theoretical Chemistry Accounts: Theory, Computation, & Modeling;May2007, Vol. 117 Issue 4, p491 

    Relativistic basis sets of double-zeta, triple-zeta, and quadruple-zeta quality have been optimized for the actinide elements Ac–Lr. The basis sets include SCF exponents for the occupied spinors and for the 7p shell, exponents of correlating functions for the valence shells (5f, 6d and...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics