TITLE

Partially linearized, fully size-extensive, and reduced multireference coupled-cluster methods. II. Applications and performance

AUTHOR(S)
Xiangzhu Li; Paldus, Josef
PUB. DATE
April 2008
SOURCE
Journal of Chemical Physics;4/14/2008, Vol. 128 Issue 14, p144119
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The partially linearized (pl), fully size-extensive multireference (MR) coupled-cluster (CC) method, fully accounting for singles (S) and doubles (D) and approximately for a subset of primary higher than doubles, referred to as plMR CCSD, as well as its plMR CCSD(T) version corrected for secondary triples, as described in Part I of this paper [X. Li and J. Paldus, J. Chem. Phys. 128, 144118 (2008)], are applied to the problem of bond breaking in the HF, F2, H2O, and N2 molecules, as well as to the H4 model, using basis sets of a DZ or a cc-pVDZ quality that enable a comparison with the full configuration interaction (FCI) exact energies for a given ab initio model. A comparison of the performance of the plMR CCSD/CCSD(T) approaches with those of the reduced MR (RMR) CCSD/CCSD(T) methods, as well as with the standard single reference (SR) CCSD and CCSD(T) methods, is made in each case. For the H4 model and N2 we also compare our results with the completely renormalized (CR) CC(2,3) method [P. Piecuch and M. WÅ‚och, J. Chem. Phys. 123, 224105 (2005)]. An important role of a proper choice of the model space for the MR-type methods is also addressed. The advantages and shortcomings of all these methods are pointed out and discussed, as well as their size-extensivity characteristics, in which case we distinguish supersystems involving noninteracting SR and MR subsystems from those involving only MR-type subsystems. Although the plMR-type approaches render fully size-extensive results, while the RMR CCSD may slightly violate this property, the latter method yields invariably superior results to the plMR CCSD ones and is more easy to apply in highly demanding cases, such as the triple-bond breaking in the nitrogen molecule.
ACCESSION #
31696058

 

Related Articles

  • Partially linearized, fully size-extensive, and reduced multireference coupled-cluster methods. I. Formalism and mutual relationship. Xiangzhu Li; Paldus, Josef // Journal of Chemical Physics;4/14/2008, Vol. 128 Issue 14, p144118 

    We describe a fully size-extensive alternative of the reduced multireference (RMR) coupled-cluster (CC) method with singles (S) and doubles (D) that generates a subset of higher-than-pair cluster amplitudes, using linearized CC equations from the full CC chain, projected onto the corresponding...

  • Accurate partial atomic charges for high-energy molecules using class IV charge models with the MIDI! basis set. Kelly, C. P.; Cramer, C. J.; Truhlar, D. G. // Theoretical Chemistry Accounts: Theory, Computation, & Modeling;Apr2005, Vol. 113 Issue 3, p133 

    We have recently developed a new class IV charge model for calculating partial atomic charges in molecules. The new model, called charge model 3 (CM3), was parameterized for calculations on molecules containing H, Li, C, N, O, F, Si, S, P, Cl, and Br by Hartree-Fock theory and by hybrid density...

  • Vibrational dependence of the H2–H2 C6 dispersion coefficients. Hinde, Robert J. // Journal of Chemical Physics;4/8/2005, Vol. 122 Issue 14, p144304 

    We use the sum-over-states formalism to compute the imaginary-frequency dipole polarizabilities for H2, as a function of the H–H bond length, at the full configuration interaction level of theory using atom-centered d-aug-cc-pVQZ basis sets. From these polarizabilities, we obtain...

  • Iterative CI general singles and doubles (ICIGSD) method for calculating the exact wave functions of the ground and excited states of molecules. Nakatsuji, Hiroshi; Ehara, Masahiro // Journal of Chemical Physics;5/15/2005, Vol. 122 Issue 19, p194108 

    The iterative configuration-interaction general singles and doubles (ICIGSD) method was applied to various closed- and open-shell electronic states of molecules within finite basis sets and was shown to give the exact results that are identical to the full CI ones. The structure of the ICIGSD is...

  • Assessment of a new approach for the two-electron cumulant in natural-orbital-functional theory. Leiva, P.; Piris, M. // Journal of Chemical Physics;12/1/2005, Vol. 123 Issue 21, p214102 

    The Piris natural orbital functional (PNOF) based on a new approach for the two-electron cumulant has been used to predict adiabatic ionization potentials, equilibrium bond distances, and harmonic vibrational frequencies of 18 diatomic molecules. Vertical ionization potentials have been...

  • The basis set superposition error in multilevel methods: a test on the H2O and HF dimer. Kim, Kyung; Kim, Yongho // Theoretical Chemistry Accounts: Theory, Computation, & Modeling;Feb2006, Vol. 115 Issue 1, p18 

    The basis set superposition error (BSSE) is often very important in the accurate calculation of dimerization energies. Accurate prediction of thermochemical properties requires appropriate consideration of the basis set incompleteness error. Multilevel methods introduce adjustable parameters to...

  • Virial exchange energies from model exact-exchange potentials. Gaiduk, Alex P.; Staroverov, Viktor N. // Journal of Chemical Physics;5/28/2008, Vol. 128 Issue 20, p204101 

    It is shown by the example of Slater’s averaged exchange potential that a poor approximation to the optimized effective potential (OEP) can yield a deceptively accurate energy via the conventional Kohn–Sham energy functional. For a trial exchange potential to be correct, its...

  • Full-dimensional ab initio potential energy surface and vibrational configuration interaction calculations for vinyl. Sharma, Amit R.; Braams, Bastiaan J.; Carter, Stuart; Shepler, Benjamin C.; Bowman, Joel M. // Journal of Chemical Physics;5/7/2009, Vol. 130 Issue 17, p174301 

    The potential energy landscape and two permutationally invariant, full-dimensional ab initio-based potential energy surfaces (PESs) for the doublet vinyl radical, C2H3, are described. The first of the two surfaces, denoted as PES/S, describes the equivalent CH2CH global minimum and the saddle...

  • Optimized effective potentials from arbitrary basis sets. Heaton-Burgess, Tim; Weitao Yang // Journal of Chemical Physics;11/21/2008, Vol. 129 Issue 19, p194102 

    We investigate the use of a regularized optimized effective potential (OEP) energy functional and L-curve procedure [T. Heaton-Burgess, F. A. Bulat, and W. Yang, Phys. Rev. Lett. 98, 256401 (2007)] for determining physically meaningful OEPs from arbitrary combinations of finite orbital and...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

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

Try another library?
Sign out of this library

Other Topics