Simulation Techniques in Parametric Hamiltonians

Abstract

Using simulation techniques, a general definition of parametric Hamiltonians (Hpa), is presented. The minimal distance between a parametric and the exact Hamiltonian (Hexa) is defined in terms of the sum of the least distance between the corresponding energy functional components. A reference electronic energy functional for simulation of Hexa is proposed based on a CI energy functional. General properties of parametric Hamiltonians are analyzed considering reduction of the number of particles, integrals, and basis set, elimination of orthogonal transformations, and correlation and total energy functionals. Parametric Hamiltonians based on simulation of binding energy functionals and a simple parametrization scheme are proposed. Some preliminary tests have been performed with the parametrization of a characterized Hpa and calculations of organic (CH4, C2H2, C2H4, and C2H6) and transition metal (Ni2 and Ni5) systems.