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Related papers: Basis set incompleteness errors in fixed-node diff…

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We have investigated the title question for both a subset of the W4-11 total atomization energies benchmark, and for the A24x8 noncovalent interactions benchmark. Overall, counterpoise corrections to post-CCSD(T) contributions are about two…

Chemical Physics · Physics 2025-01-07 Vladimir Fishman , Emmanouil Semidalas , Margarita Shepelenko , Jan M. L. Martin

We have developed and benchmarked a new extended basis set for explicitly correlated calculations, namely cc-pV5Z-F12. It is offered in two variants, cc-pV5Z-F12 and cc- pV5Z-F12(rev2), the latter of which has additional basis functions on…

Chemical Physics · Physics 2015-07-16 Kirk A. Peterson , Manoj Kumar Kesharwani , Jan M. L. Martin

Accurate determination of electronic properties of correlated oxides remains a significant challenge for computational theory. Traditional Hubbard-corrected density functional theory (DFT+U) frequently encounters limitations in precisely…

Materials Science · Physics 2024-03-19 Hyeondeok Shin , Kevin Gasperich , Tomas Rojas , Anh T. Ngo , Jaron T. Krogel , Anouar Benali

Local electronic-structure methods in quantum chemistry operate on the ability to compress electron correlations more efficiently in a basis of spatially localized molecular orbitals than in a parent set of canonical orbitals. However, many…

Chemical Physics · Physics 2024-08-01 Jonas Greiner , Jürgen Gauss , Janus J. Eriksen

Molecule-optimized basis sets, based on approximate natural orbitals, are developed for accelerating the convergence of quantum calculations with strongly correlated (multi-referenced) electrons. We use a low-cost approximate solution of…

Chemical Physics · Physics 2014-02-12 Gergely Gidofalvi , David A. Mazziotti

We present two Diffusion Monte Carlo (DMC) algorithms for systems of ultracold quantum gases featuring synthetic spin-orbit interactions. The first one is a discrete spin generalization of the T- moves spin-orbit DMC, which provides an…

Quantum Gases · Physics 2018-12-05 J. Sanchez-Baena , J. Boronat , F. Mazzanti

We have carried out quantum Monte Carlo (QMC) calculations of silicon crystal focusing on the accuracy and systematic biases that affect the electronic structure characteristics. The results show that 64 and 216 atom supercells provide an…

Materials Science · Physics 2021-05-26 Abdulgani Annaberdiyev , Guangming Wang , Cody A. Melton , M. Chandler Bennett , Lubos Mitas

Using the homogeneous electron gas (HEG) as a model, we investigate the sources of error in the `initiator' adaptation to Full Configuration Interaction Quantum Monte Carlo (i-FCIQMC), with a view to accelerating convergence. In particular…

Computational Physics · Physics 2012-06-26 James J. Shepherd , George H. Booth , Ali Alavi

This paper aims to establish a first general error estimate for numerical approximations of the system of reaction-diffusion equations (SRDEs), using reasonable regularity assumptions on the exact solutions. We employ the gradient…

Analysis of PDEs · Mathematics 2025-01-24 Yahya Alnashri

Due to their diverse nature, the faithful description of excited states within electronic structure theory methods remains one of the grand challenges of modern theoretical chemistry. Quantum Monte Carlo (QMC) methods have been applied very…

Chemical Physics · Physics 2020-06-05 Anthony Scemama , Michel Caffarel , Anouar Benali , Denis Jacquemin , Pierre-François Loos

In a recent paper, we proposed the adaptive shift method for correcting the undersampling bias of the initiator-FCIQMC. The method allows faster convergence with the number of walkers to the FCI limit than the normal initiator method,…

Computational Physics · Physics 2021-02-03 Khaldoon Ghanem , Kai Guther , Ali Alavi

The mean field limits of systems of interacting diffusions (also called stochastic interacting particle systems (SIPS)) have been intensively studied since McKean \cite{mckean1966class}. The interacting diffusions pave a way to…

Probability · Mathematics 2021-04-06 Lukasz Szpruch , Shuren Tan , Alvin Tse

We present a detailed study of the energetics of water clusters (H$_2$O)$_n$ with $n \le 6$, comparing diffusion Monte Carlo (DMC) and approximate density functional theory (DFT) with well converged coupled-cluster benchmarks. We use the…

Materials Science · Physics 2015-06-04 M. J. Gillan , F. R. Manby , M. D. Towler , D. Alfè

We report a scalable Fortran implementation of the phaseless auxiliary-field quantum Monte Carlo (ph-AFQMC) and demonstrate its excellent performance and beneficial scaling with respect to system size. Furthermore, we investigate…

Chemical Physics · Physics 2024-02-09 Z. Sukurma , M. Schlipf , M. Humer , A. Taheridehkordi , G. Kresse

We perform the fixed-node diffuse Monte Carlo (FN DMC) calculations to determine the barrier height and reaction energy of a critical reaction, the H-transfer reaction from syn-CH3CHOO to vinyl hydroperoxide. The FN DMC barrier height is…

Chemical Physics · Physics 2021-06-23 Zhiping Wang , Yuxiang Bu

Strong magnetic fields such as those found on white dwarfs have significant effects on the electronic structure of atoms and molecules. However, the vast majority of molecular studies in the literature in such fields are carried out with…

Chemical Physics · Physics 2025-02-07 Hugo Åström , Susi Lehtola

This article focuses on the finite volume method (FVM) as an instrument tool to deal with the non-linear collisional-induced breakage equation (CBE) that arises in the particulate process. Notably, we consider the non-conservative…

Numerical Analysis · Mathematics 2024-11-27 Sanjiv Kumar Bariwal , Rajesh Kumar

For the theoretical understanding of the reactivity of complex chemical systems accurate relative energies between intermediates and transition states are required. Despite its popularity, density functional theory (DFT) often fails to…

Chemical Physics · Physics 2016-06-23 Gregor N. Simm , Markus Reiher

Broken-symmetry (BS) approaches are widely employed to evaluate Heisenberg exchange parameters, primarily in combination with DFT calculations. For many magnetic materials, BS-DFT calculations give reasonable estimations of exchange…

Chemical Physics · Physics 2025-06-02 Naoya Iwahara , Zhishuo Huang , Akseli Mansikkamäki , Liviu F. Chibotaru