Gábor Tóth

Publications (2)6.67 Total impact

• Source

  Available from: Debashis Mukherjee

  Article: Comparison of low-order multireference many-body perturbation theories.

  Rajat K Chaudhuri, Karl F Freed, Gabriel Hose, Piotr Piecuch, Karol Kowalski, Marta Włoch, Sudip Chattopadhyay, Debashis Mukherjee, Zoltán Rolik, Agnes Szabados, Gábor Tóth, Péter R Surján
  [show abstract] [hide abstract]
  ABSTRACT: Tests have been made to benchmark and assess the relative accuracies of low-order multireference perturbation theories as compared to coupled cluster (CC) and full configuration interaction (FCI) methods. Test calculations include the ground and some excited states of the Be, H(2), BeH(2), CH(2), and SiH(2) systems. Comparisons with FCI and CC calculations show that in most cases the effective valence shell Hamiltonian (H(v)) method is more accurate than other low-order multireference perturbation theories, although none of the perturbative methods is as accurate as the CC approximations. We also briefly discuss some of the basic differences among the multireference perturbation theories considered in this work.
  The Journal of Chemical Physics 05/2005; 122(13):134105. · 3.33 Impact Factor
• Source

  Available from: elte.hu

  Article: Multiconfiguration perturbation theory: size consistency at second order.

  Agnes Szabados, Zoltán Rolik, Gábor Tóth, Péter R Surján
  [show abstract] [hide abstract]
  ABSTRACT: A modified version of a previously elaborated multiconfiguration perturbation theory (MCPT) [Rolik et al. J. Chem. Phys. 119, 1922 (2003)] is presented. In the modified formulation size consistency is ensured at second order in energy, by omitting projectors from the zero order Hamiltonian operator. This MCPT formulation is abbreviated as SC2-MCPT (size consistent at second order). To ensure proper separability, we also require that energy denominators are constructed as differences of some one-particle energies. A similar choice for energy denominators also renders the well-known multireference Moller-Plesset (MRMP) energy size consistent at second order. The same thing applies to the related multireference perturbation theory by Witek, Nakano, and Hirao.
  The Journal of Chemical Physics 04/2005; 122(11):114104. · 3.33 Impact Factor