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We introduce an alternative approach to the first-principles calculation of NMR shielding tensors. These are obtained from the derivative of the orbital magnetization with respect to the application of a microscopic, localized magnetic…

Materials Science · Physics 2009-09-08 T. Thonhauser , D. Ceresoli , Arash A. Mostofi , Nicola Marzari , R. Resta , David Vanderbilt

We report an implementation of the nuclear magnetic resonance (NMR) shielding ($\sigma$), isotope-independent indirect spin-spin coupling ($K$) and the magnetizability ($\xi$) tensors in the frozen density embedding (FDE) scheme using the…

Chemical Physics · Physics 2017-08-02 Malgorzata Olejniczak , Radovan Bast , Andre Severo Pereira Gomes

Using the shift-operator technique, a compact formula for the Fourier transform of a product of two Slater-type orbitals located on different atomic centers is derived. The result is valid for arbitrary quantum numbers and was found to be…

Materials Science · Physics 2009-11-13 T. A. Niehaus , R. López , J. F. Rico

Three-centre nuclear attraction integrals, which arise in density functional and \textit{ab initio} calculations, are one of the most time-consuming computations involved in molecular electronic structure calculations. Even for relatively…

Numerical Analysis · Mathematics 2024-12-20 Jordan Lovrod , Hassan Safouhi

The auxiliary functions provide efficient computation of integrals arising at the self-consistent field (SCF) level for molecules using Slater-type bases. This applies both in relativistic and non-relativistic electronic structure theory.…

Chemical Physics · Physics 2017-11-29 A. Bagci , P. E. Hoggan

The Slater-type orbital basis with non-integer principal quantum numbers is a physically and mathematically motivated choice for molecular electronic structure calculations in both non-relativistic and relativistic theory. The…

Quantum Physics · Physics 2022-03-15 A Bagci , Philip E Hoggan , M Adak

Ab initio QED calculations of the nuclear magnetic shielding constant in helium-like ions are presented. We combine the nonrelativistic QED approach based on an expansion in powers of the fine-structure constant $\alpha$ and the so-called…

Atomic Physics · Physics 2024-04-26 Vladimir A. Yerokhin , Krzysztof Pachucki , Zoltán Harman , Christoph H. Keitel

The main aim of this paper is to develop a framelet representation of the tensor nuclear norm for third-order tensor completion. In the literature, the tensor nuclear norm can be computed by using tensor singular value decomposition based…

Image and Video Processing · Electrical Eng. & Systems 2020-08-25 Tai-Xiang Jiang , Michael K. Ng , Xi-Le Zhao , Ting-Zhu Huang

We perform a recursive reduction of one-loop $n$-point rank $R$ tensor Feynman integrals [in short: $(n,R)$-integrals] for $n\leq 6$ with $R\leq n$ by representing $(n,R)$-integrals in terms of $(n,R-1)$- and $(n-1,R-1)$-integrals. We use…

High Energy Physics - Phenomenology · Physics 2010-01-07 T. Diakonidis , J. Fleischer , T. Riemann , J. B. Tausk

We report on a formulation and implementation of a scheme to compute NMR shieldings at second-order Moller-Plesset (MP2) perturbation theory using gauge-including atomic orbitals (GIAOs) to ensure gauge-origin independence and Cholesky…

Chemical Physics · Physics 2024-06-19 Sophia Burger , Filippo Lipparini , Jürgen Gauss , Stella Stopkowicz

The present article proposes a partial answer to the explicit inversion of the tensor tomography problem in two dimensions, by proving injectivity over certain kinds of tensors and providing reconstruction formulas for them. These tensors…

Analysis of PDEs · Mathematics 2015-06-18 François Monard

In any ab initio molecular orbital (MO) calculations, the major task involves the computation of the so-called molecular multi-center integrals. Multi-center integral calculations is a very challenging mathematical problem in nature.…

Computational Physics · Physics 2022-04-26 Richard M. Slevinsky , Hassan Safouhi

Within the lowest-order relativistic approximation ($\sim v^2/c^2$) and to first order in $m_e/M$, the tensorial form of the relativistic corrections of the nuclear recoil Hamiltonian is derived, opening interesting perspectives for…

Atomic Physics · Physics 2015-05-28 E. Gaidamauskas , C. Nazé , P. Rynkun , G. Gaigalas , P. Jönsson , M. Godefroid

A simple method is outlined for analytic evaluation of the basic 2-electron atomic integral with integrand containing products of atomic s-type Slater orbitals and exponentially correlated function of the form $r_{ij}…

Atomic Physics · Physics 2016-09-02 Bholanath Padhy

We describe an accurate and scalable implementation for the computation of molecular nuclear magnetic resonance shieldings, J-couplings, and magnetizabilities within nonrelativistic semilocal density functional theory, based on numeric…

Computational Physics · Physics 2020-02-25 Raul Laasner , William Huhn , Johannes Colell , Thomas Theis , Victor Yu , Warren Warren , Volker Blum

We present a benchmark of the density functional linear response calculation of NMR shieldings within the Gauge-Including Projector-Augmented-Wave method against all-electron Augmented-Plane-Wave$+$local-orbital and uncontracted Gaussian…

Materials Science · Physics 2017-03-08 G. A. de Wijs , R. Laskowski , P. Blaha , R. W. A. Havenith , G. Kresse , M. Marsman

Standard numerical integrators suffer from an order reduction when applied to nonlinear Schr\"{o}dinger equations with low-regularity initial data. For example, standard Strang splitting requires the boundedness of the solution in $H^{r+4}$…

Numerical Analysis · Mathematics 2019-06-04 Marvin Knöller , Alexander Ostermann , Katharina Schratz

We consider rank-one non-symmetric tensor estimation and derive simple formulas for the mutual information. We start by the order 2 problem, namely matrix factorization. We treat it completely in a simpler fashion than previous proofs using…

Information Theory · Computer Science 2018-11-28 Jean Barbier , Nicolas Macris , Léo Miolane

We present a theory of nuclear magnetic resonance (NMR) shielding tensors for electronic states with arbitrary degeneracy. The shieldings are here expressed in terms of generalized Zeeman ($g^{(k)}$) and hyperfine ($A^{(k)}$) tensors, of…

Chemical Physics · Physics 2012-11-28 Willem Van den Heuvel , Alessandro Soncini

We present a theory for the temperature-dependent nuclear magnetic shielding tensor of molecules with arbitrary electronic structure. The theory is a generalization of Ramsey's theory for closed-shell molecules. The shielding tensor is…

Chemical Physics · Physics 2014-03-12 Willem Van den Heuvel , Alessandro Soncini
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