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The Atom-Calibrated Basis-set Extrapolation (ACBE) method is introduced as a robust approach for extrapolating MP2 correlation energies from small basis sets. Unlike conventional extrapolation techniques, ACBE incorporates system- and…

Chemical Physics · Physics 2025-04-07 E. Fabiano , F. Della Sala

Ab initio calculations including electron correlation are still extremely costly except for the smallest atoms and molecules. Therefore, our purpose in the present study is to employ a bond-order correlation approach to obtain, via…

Chemical Physics · Physics 2007-05-23 A. Grassi , G. M. Lombardo , G. Forte , G. G. N. Angilella , R. Pucci , N. H. March

In this work we propose a novel composite method for accurate calculation of the energies of many-electron atoms. The dominant contribution to the energy (pair energies) are calculated by using explicitly correlated factorisable coupled…

Atomic Physics · Physics 2018-12-12 Michal Przybytek , Michal Lesiuk

Using a new analytic quantum mechanical method based on Slater's Xalpha method, we show that a fairly accurate estimate of the total energy of a molecule can be obtained from the exact energies of its constituent atoms. The mean absolute…

Materials Science · Physics 2009-11-11 Rajendra R. Zope , Brett I. Dunlap

Calibration ab initio (direct coupled cluster) calculations including basis set extrapolation, relativistic effects, inner-shell correlation, and an anharmonic zero-point energy, predict the total atomization energy at 0 K of SO$_3$ to be…

Chemical Physics · Physics 2009-10-31 Jan M. L. Martin

The recently developed semistochastic heat-bath configuration interaction (SHCI) method is a systematically improvable selected configuration interaction plus perturbation theory method capable of giving essentially exact energies for…

Chemical Physics · Physics 2020-10-01 Yuan Yao , Emmanuel Giner , Junhao Li , Julien Toulouse , C. J. Umrigar

Two new schemes for computing molecular total atomization energies (TAEs) and/or heats of formation ($\Delta H^\circ_f$) of first-and second-row compounds to very high accuracy are presented. The more affordable scheme, W1 (Weizmann-1)…

Chemical Physics · Physics 2009-10-31 Jan M. L. Martin , Glenisson de Oliveira

Scalar relativistic corrections to atomization energies of 1st-and 2nd-row molecules can be rationalized in terms of a simple additive model, linear in changes in atomic s populations. In a sample of 200 first-and second-row molecules, such…

Chemical Physics · Physics 2018-08-13 Jan M. L. Martin , Nitai Sylvetsky

We have studied electron correlations in the doped two-dimensional (2D) Hubbard model by using the coupled-cluster method (CCM) to investigate whether or not the method can be applied to correct the independent particle approximations…

Strongly Correlated Electrons · Physics 2009-10-31 Yoshihiro Asai , Hideki Katagiri

Nuclear many-body calculations are computationally demanding. An estimate of their accuracy is often hampered by the limited amount of computational resources even on present-day supercomputers. We provide an extrapolation method based on…

Nuclear Theory · Physics 2009-11-10 H. Zhan , A. Nogga , B. R. Barrett , J. P. Vary , P. Navratil

We construct a reference benchmark set for atomic and molecular random-phase-approximation (RPA) correlation energies in a density functional theory (DFT) framework at the complete basis set limit. This set is used to evaluate the accuracy…

Chemical Physics · Physics 2013-02-22 E. Fabiano , F. Della Sala

First-principles calculations are a cornerstone of modern surface science and heterogeneous catalysis. However, accurate reaction energies and barrier heights are frequently inaccessible due to the approximations demanded by the large…

Materials Science · Physics 2024-02-08 Hong-Zhou Ye , Timothy C. Berkelbach

Accurate thermochemical data with sub-chemical accuracy (within 1 kcal mol$^{-1}$ of the empirical ground truth) are essential for advancing computational chemistry methods. However, existing datasets that reach this level of accuracy…

We study alchemical atomic energy partitioning as a method to estimate atomisation energies from atomic contributions which are defined in physically rigorous and general ways through use of the uniform electron gas as a joint reference. We…

We employ correlation-consistent effective core potentials (ccECPs) to perform exact or nearly exact correlation and total energy calculations for the fifth-row elements (Rb-Xe). Total energies are calculated using various correlated…

Materials Science · Physics 2025-12-22 Aqsa Shaikh , Omar Madany , Benjamin Kincaid , Lubos Mitas

The energy calibration and resolution of the electromagnetic calorimeter (ECAL) of the CMS detector have been determined using proton-proton collision data from LHC operation in 2010 and 2011 at a centre-of-mass energy of sqrt(s)=7 TeV with…

High Energy Physics - Experiment · Physics 2013-10-07 CMS Collaboration

The accuracy of the Faddeev random phase approximation (FRPA) method is tested by calculating the total and ionization energies of a set of light atoms up to Ar. Comparisons are made with the results of coupled-cluster singles and doubles…

Chemical Physics · Physics 2015-05-18 C. Barbieri , D. Van Neck , M. Degroote

An ab initio approach formulated under an entropy-inspired repartitioning of the electronic Hamiltonian is presented. This ansatz produces orbital eigenvalues each shifted by entropic contributions expressed as subsets of scaled pair…

Chemical Physics · Physics 2025-06-10 Abdulrahman Y. Zamani , Kevin Carter-Fenk

The total atomization energy at absolute zero, (TAE$_0$) of benzene, C$_6$H$_6$, was computed fully {\em ab initio} by means of W2h theory as 1306.6 kcal/mol, to be compared with the experimentally derived value 1305.7+/-0.7 kcal/mol. The…

Chemical Physics · Physics 2009-11-07 S. Parthiban , J. M. L. Martin

The energy calibration of calorimeters at collider experiments, such as the ones at the CERN Large Hadron Collider, is crucial for achieving the experiments physics objectives. Standard calibration approaches have limitations that become…

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