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Attaining a reliable complete basis set (CBS) limit remains a significant challenge in ab initio correlated electronic-structure calculations. Building on our previous work for atoms and diatomic molecules, we present a finite-element (FE)…

Materials Science · Physics 2026-03-30 Hao Peng , Haochen Liu , Chuhao Li , Hehu Xie , Xinguo Ren

In this article we address the general approach for calculating dynamical dipole polarizabilities of small quantum systems, based on a sum-over-states formula involving in principle the entire energy spectrum of the system. We complement…

Quantum Physics · Physics 2017-07-10 R. Vexiau , D. Borsalino , M. Lepers , A. Orbán , M. Aymar , O. Dulieu , N. Bouloufa-Maafa

Novel equations for the electric dipole polarizability $\alpha_{_{E1}}$ of low-lying excited states in atomic nuclei -- and the related $(-2)$ moment of the total photo-absorption cross section, $\sigma_{_{-2}}$ -- are inferred in terms of…

Nuclear Theory · Physics 2024-03-12 José Nicolás Orce , Cebo Ngwetsheni

We show that the Gaussian Approximation Potential machine learning framework can describe complex magnetic potential energy surfaces, taking ferromagnetic iron as a paradigmatic challenging case. The training database includes total…

Materials Science · Physics 2018-02-07 Daniele Dragoni , Thomas D. Daff , Gabor Csanyi , Nicola Marzari

Accuracy of molecular dynamics simulations depends crucially on the interatomic potential used to generate forces. The gold standard would be first-principles quantum mechanics (QM) calculations, but these become prohibitively expensive at…

Energy loss of energetic ions in solid is crucial in many field, and accurate prediction of the ion stopping power is a long-time goal. Though great efforts have been made, it is still very difficult to find a universal prediction model to…

Applied Physics · Physics 2020-10-21 Xun Guo , Hao Wang , Shijun Zhao , Ke Jin , Jianming Xue

We extend the capabilities of correlation energy functionals based on the adiabatic-connection fluctuation-dissipation theorem by implementing the analytical atomic forces within the random phase approximation (RPA), in the context of plane…

Materials Science · Physics 2026-03-19 Damian Contant , Maria Hellgren

We recently introduced the Alchemical Integral Transform (AIT) enabling the prediction of energy differences, and guessed an Ansatz to parametrize space $\pmb{r}$ in some alchemical change $\lambda$. Here, we present a rigorous derivation…

Chemical Physics · Physics 2024-12-10 Simon León Krug , O. Anatole von Lilienfeld

In the last decades, dynamical mean-field theory (DMFT) and its diagrammatic extensions have been successfully applied to describe local and nonlocal correlation effects in correlated electron systems. Unfortunately, except for the exact…

Strongly Correlated Electrons · Physics 2022-11-02 Julian Stobbe , Georg Rohringer

In this work we consider a numerically solvable model of a two-electron diatomic molecule to study a recently proposed approximation based on the density-functional theory of so-called strictly correlated electrons (SCE). We map out the…

Strongly Correlated Electrons · Physics 2019-02-13 Luis Cort , Soeren Ersbak Bang Nielsen , Robert van Leeuwen

The "catastrophe" in solving the Dirac equation for an electron in the field of a point electric charge, which emerges for the charge numbers Z > 137, is removed in this work by effective accounting of finite dimensions of nuclei. For this…

General Physics · Physics 2017-08-23 V. P. Neznamov , I. I. Safronov

We compute the expectations of the squares of the electric and magnetic fields in the vacuum region outside a half-space filled with a uniform non-dispersive dielectric. This gives predictions for the Casimir-Polder force on an atom in the…

High Energy Physics - Theory · Physics 2008-11-26 Adam D. Helfer , Andrew S. I. D. Lang

It was recently shown that the exact potential driving the electron's dynamics in enhanced ionization of H$_2^+$ can have large contributions arising from dynamical electron-nuclear correlation, going beyond what any electrostatics-based…

Atomic and Molecular Clusters · Physics 2017-06-07 E. Khosravi , A. Abedi , A. Rubio , N. T. Maitra

Exact ground-state properties are presented by combining the diagonalization in the Fock space (and taking all hopping integrals and all two-site interactions) with the ab initio optimization of the Wannier functions. Electrons are…

Strongly Correlated Electrons · Physics 2007-05-23 Jozef Spalek , Adam Rycerz

Analytical solutions of the Bohr Hamiltonian are obtained in the $\gamma$-unstable case, as well as in an exactly separable rotational case with $\gamma\approx 0$, called the exactly separable Morse (ES-M) solution. Closed expressions for…

Nuclear Theory · Physics 2008-11-26 I. Boztosun , D. Bonatsos , I. Inci

We present an efficient implementation of the second- and third-order single-reference algebraic diagrammatic construction theory for electron attachment (EA) and ionization (IP) energies and spectra (EA/IP-ADC(n), n = 2, 3). Our new…

Chemical Physics · Physics 2021-07-12 Samragni Banerjee , Alexander Yu. Sokolov

Electronic structure methods for accurate calculation of molecular properties have a high cost that grows steeply with the problem size, therefore, it is helpful to have the underlying atomic basis functions that are less in number but of…

Chemical Physics · Physics 2019-03-15 Dimitri N. Laikov

We present a new scheme to extract numerically ``optimal'' interatomic potentials from large amounts of data produced by first-principles calculations. The method is based on fitting the potential to ab initio atomic forces of many atomic…

Condensed Matter · Physics 2009-10-22 Furio Ercolessi , James B. Adams

We present a comprehensive a priori error analysis of a practical energy based atomistic/continuum coupling method (Shapeev, arXiv:1010.0512) in two dimensions, for finite-range pair-potential interactions, in the presence of vacancy…

Numerical Analysis · Mathematics 2011-04-05 Christoph Ortner , Alexander V. Shapeev

Reliable first-principles calculations of electrochemical processes require accurate prediction of the interfacial capacitance, a challenge for current computationally-efficient continuum solvation methodologies. We develop a model for the…

Chemical Physics · Physics 2018-04-12 Ravishankar Sundararaman , Kendra Letchworth-Weaver , Kathleen Schwarz