Correlation energy extrapolation by intrinsic scaling. V. Electronic energy, atomization energy, and enthalpy of formation of water

2006 ◽  
Vol 124 (17) ◽  
pp. 174304 ◽  
Author(s):  
Laimutis Bytautas ◽  
Klaus Ruedenberg
Keyword(s):  
Enthalpy Of Formation ◽  
Correlation Energy ◽  
Electronic Energy ◽  
Atomization Energy ◽  
Energy Extrapolation

Electronic Structure Benchmark Calculations of Inorganic and Biochemical Carboxylation Reactions

2018 ◽  
Author(s):  
Oscar A. Douglas-Gallardo ◽  
David A. Sáez ◽  
Stefan Vogt-Geisse ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Electronic Structure ◽  
Chemical Reactions ◽  
Density Functional ◽  
Correlation Energy ◽  
Electronic Energy ◽  
Basis Sets ◽  
Electronic Correlation ◽  
Correct Description ◽  
Carbon Dioxide Co2 ◽  
High Level

<div><div><div><p>Carboxylation reactions represent a very special class of chemical reactions that is characterized by the presence of a carbon dioxide (CO2) molecule as reactive species within its global chemical equation. These reactions work as fundamental gear to accomplish the CO2 fixation and thus to build up more complex molecules through different technological and biochemical processes. In this context, a correct description of the CO2 electronic structure turns out to be crucial to study the chemical and electronic properties associated with this kind of reactions. Here, a sys- tematic study of CO2 electronic structure and its contribution to different carboxylation reaction electronic energies has been carried out by means of several high-level ab-initio post-Hartree Fock (post-HF) and Density Functional Theory (DFT) calculations for a set of biochemistry and inorganic systems. We have found that for a correct description of the CO2 electronic correlation energy it is necessary to include post-CCSD(T) contributions (beyond the gold standard). These high-order excitations are required to properly describe the interactions of the four π-electrons as- sociated with the two degenerated π-molecular orbitals of the CO2 molecule. Likewise, our results show that in some reactions it is possible to obtain accurate reaction electronic energy values with computationally less demanding methods when the error in the electronic correlation energy com- pensates between reactants and products. Furthermore, the provided post-HF reference values allowed to validate different DFT exchange-correlation functionals combined with different basis sets for chemical reactions that are relevant in biochemical CO2 fixing enzymes.</p></div></div></div>

scholarly journals Correlation Energy Extrapolation by Many-Body Expansion

2017 ◽  
Vol 121 (4) ◽  
pp. 836-844 ◽  
Author(s):  
Jeffery S. Boschen ◽  
Daniel Theis ◽  
Klaus Ruedenberg ◽  
Theresa L. Windus
Keyword(s):  
Correlation Energy ◽  
Many Body ◽  
Energy Extrapolation

Efficient Electronic Energy Functionals for Tight-Binding

1997 ◽  
Vol 491 ◽  
Author(s):  
Roger Haydock
Keyword(s):  
Ground State ◽  
State Energy ◽  
Correlation Energy ◽  
Tight Binding ◽  
Electronic Energy ◽  
Wave Functions ◽  
Electronic Charge ◽  
Energy Functionals ◽  
Exchange Correlation ◽  
Band Structure Energy

ABSTRACTGeneralized functionals are constructed from the exchange-correlation energy by a Legendre transformation which makes the new functionals stationary at the electronic charge density, potential, and wave functions for the ground-state. Using generalized functionals, the density, potential, and wave functions can be independently parameterized and varied to determine the ground-state energy-surface for a system of atoms. This eliminates the computationally awkward steps of constructing densities from wave functions or potentials from densities, and is particularly well suited to parameterizations using tight-binding orbitale together with atomic-like densities and potentials. For each choice of parameters, the only quantities which must be computed are the electron-electron energy for the density, the integral of the potential over the density, and the band structure energy for the wave functions. To second order in the density, potential, and wave functions, the energy for a configuration of atoms is given by the generalized functional evaluated at a superposition of atomic densities, a potential made by stitching together the atomic potentials where they are equal, and atomic wave functions. For more accurate stationary energies the densities, potentials, and wave functions can be improved by one or more conjugate gradient steps.

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