Article
Chemistry, Physical
Jing Yang, Stefano Falletta, Alfredo Pasquarello
Summary: In this study, the accuracy of range-separated hybrid functionals in predicting band gaps of semiconducting and insulating materials is systematically evaluated and compared with their global counterparts. It is observed that range-separated hybrid functionals that accurately describe long-range dielectric screening significantly outperform standard hybrid functionals such as PBE0 and HSE06. The choice of short-range Fock exchange fraction and screening length can further reduce the prediction error. A universal expression for selecting the inverse screening parameter is proposed, resulting in a mean absolute error as small as 0.15 eV for band gap prediction.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Wenna Ai, Wei-Hai Fang, Neil Qiang Su
Summary: This study focuses on the range-separated correlation in long-range corrected hybrid functionals, presenting a theory on its derivation and proving its reliability and effectiveness. The new functional proposed in this work outperforms the traditional LC-BLYP method in various tests and maintains important properties of the XC potential.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Wenna Ai, Wei-Hai Fang, Neil Qiang Su
Summary: The short-range corrected reduced density matrix functional omega P22 is developed to utilize the advantages of functionals in KS-DFT and RDMFT without double-counting, outperforming other 1-RDM functionals in tests of thermochemistry, nonbonded interactions, and bond dissociation energy. Omega P22 shows less systematic error for systems involving fractional spins and can accurately predict the energies for different single and multiple bonds, filling a gap left by commonly used KS-DFT and RDMFT functionals.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Katarzyna Pernal, Michal Hapka
Summary: Range-separated multiconfigurational density functional theory (RS MC-DFT) combines density functional and wavefunction theories by partitioning the electron interaction operator and modeling with different methods. RS MC-DFT aims to increase versatility and accuracy of methods while reducing computational cost. Variants of RS MC-DFT can be divided into single-determinant-based and multideterminantal approaches for describing electron correlation energy. Applications include ground-state properties of molecules and noncovalent interactions, as well as time-dependent linear-response theory and direct approaches to excited states. Advantages of RS MC-DFT over conventional DFT and ab initio methods are assessed for each area of application.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2022)
Article
Chemistry, Physical
Jiawei Zhan, Marco Govoni, Giulia Galli
Summary: Electronic structure calculations based on DFT have successfully predicted ground-state properties of molecules and materials. However, the currently used exchange and correlation functionals are often inaccurate for describing the electronic properties of heterogeneous solids. Here, we present a dielectric-dependent range-separated hybrid functional, SE-RSH, which accurately predicts the electronic structure of various nonmetallic interfaces, solids, and nanoparticles.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
David Mester, Mihaly Kallay
Summary: The spin-scaling techniques in the RS-DH method have shown robustness and reduced computational expenses, improving the functional methods and having a broad application scope.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Physical
Karno Schwinn, Felipe Zapata, Antoine Levitt, Eric Cances, Eleonora Luppi, Julien Toulouse
Summary: This article explores the merits of linear-response range-separated time-dependent density-functional theory (TDDFT) for calculating photoionization spectra. Two variants of range-separated TDDFT are considered and compared with standard methods. The article demonstrates the calculation of photoionization spectra using the Sternheimer approach and applies it to the photoionization spectrum of the Be atom. The results show significant improvement over traditional methods.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
David Mester, Mihaly Kallay
Summary: A simple and robust range-separated double-hybrid time-dependent density functional approach is proposed for accurate calculation of excitation energies. The new approach shows improvement over standard double hybrids and provides a more robust and accurate alternative in most cases, surpassing existing range-separated hybrid and double-hybrid functionals on average.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Physical
Daniel Gibney, Jan-Niklas Boyn, David A. Mazziotti
Summary: Researchers demonstrate how to transform DFT into a one-electron reduced-density-matrix (1-RDM) functional theory to address the limitations of accurately describing the electronic structure of strongly correlated systems. This method retains favorable computational scaling compared to traditional DFT and achieves substantial improvements in the description of static correlation in chemical structures and processes.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Marvin Friede, Sebastian Ehlert, Stefan Grimme, Jan-Michael Mewes
Summary: This study investigates the interdependency between dispersion correction parameters and the range-separation parameter omega in large molecules. The results show that some functionals are strongly affected by omega values, leading to overbinding and poor performance. Strategies to mitigate these issues are discussed, providing insights for future improvements.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Susanne Furst, Martin Kaupp
Summary: The recently reported ?LH22t range-separated local hybrid functional can provide results for ionization energies, electron affinities, and fundamental gaps that are comparable to OT-RSH methods, approaching the quality of GW results, without the need for system-specific tuning. This functional also gives excellent outer-valence quasiparticle spectra and is accurate for various excitation types, making it a promising new tool in molecular electronics.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Sergio D. Pineda Flores
Summary: Chembot is a machine learning-based approach to selective configuration interaction that outperforms its purely stochastic counterpart in terms of convergence iterations, determinants in the variational space, and important configurations required to achieve the same energy. It utilizes novel choices such as the use of support vector machine, charge density matrix, and configuration energy as features to achieve near full configuration interaction quality energies.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Physical
Julien Toulouse, Karno Schwinn, Felipe Zapata, Antoine Levitt, Eric Cances, Eleonora Luppi
Summary: This paper discusses the calculations of photoionization spectra and core resonances of open-shell systems using range-separated time-dependent density-functional theory. By employing the time-dependent range-separated hybrid and time-dependent locally range-separated hybrid schemes, along with a spin-unrestricted linear-response Sternheimer approach in a non-orthogonal B-spline basis set, efficient calculations can be performed and satisfactory results can be obtained.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
David Mester, Mihaly Kallay
Summary: This paper combines second-order algebraic-diagrammatic construction with range-separation techniques to propose a new double-hybrid method. Through testing, it is found that range separation for correlation contributions is highly effective for both the ADC(2)-based DH approaches and the genuine DH approaches.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Chandrima Chakravarty, Huseyin Aksu, Buddhadev Maiti, Barry D. Dunietz
Summary: The electronic spectra of C-60 thin films were computationally studied using a combination of density functional theory (DFT) with a screened range separated hybrid (SRSH) functional and a polarizable continuum model (PCM). The results showed excellent correspondence between the frontier orbital's energy levels and the molecular system's ionization potential and electron affinity, leading to high quality electronic excitation energies.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Physical
Diata Traore, Emmanuel Giner, Julien Toulouse
Summary: This article re-examines the basis-set correction theory based on density-functional theory and proposes an improved variant of basis-set correction. It also demonstrates how to develop a local-density approximation using the basis-set correction method.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Tanner Culpitt, Laurens D. M. Peters, Erik I. Tellgren, Trygve Helgaker
Summary: The study investigates the properties of the diagonal nonadiabatic term in the Born-Oppenheimer wave function ansatz, deriving analytic expressions for the Berry curvature and DBOC and calculating their properties in several molecules based on magnetic field strength and bond distance. The results indicate that the characteristics of DBOC and Berry curvature vary between molecules and instances of broken time-reversal symmetry are identified in the dissociation curves of BH and CH+.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Stanislaw Dembinski, Jacek Karwowski, Jozef Szudy, Trygve Helgaker
Summary: This paper presents the life and works of Lutoslaw Wolniewicz, a prominent quantum chemist known for his groundbreaking research on the structure and spectra of the hydrogen molecule and its isotopomers.
Review
Chemistry, Multidisciplinary
Filip Cernatic, Bruno Senjean, Vincent Robert, Emmanuel Fromager
Summary: This article reviews recent progress in the field of (time-independent) ensemble density-functional theory (DFT) for excited states, focusing on the GOK and N-centered ensemble formalisms. Key exact results are highlighted, and the article discusses in detail the variational evaluation of orbital-dependent ensemble Hartree-exchange (Hx) energies and the possibility of improving existing theories using the concept of density-driven correlation.
TOPICS IN CURRENT CHEMISTRY
(2022)
Article
Chemistry, Physical
Diata Traore, Julien Toulouse, Emmanuel Giner
Summary: This study proposes an approach to accelerate the computation of molecular properties in wave-function theory by using a basis-set correction based on density-functional theory. Numerical tests on dipole moments in coupled-cluster with single, double, and perturbative triple excitations show a clear improvement in basis convergence.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Miles J. Pemberton, Tom J. P. Irons, Trygve Helgaker, Andrew M. Teale
Summary: A novel implementation for calculating molecular gradients under strong magnetic fields is used to optimize molecular structures that change significantly under these conditions. By employing an analog of the ab initio random structure search, the most stable structures for He-n and CHn systems at high magnetic field strengths are determined to be in high-spin states with a planar geometry aligned perpendicular to the field. The electron and current densities of these systems are also investigated to explain chemical bonding in strong magnetic fields and provide insight into exotic chemistry in extreme environments.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Karno Schwinn, Felipe Zapata, Antoine Levitt, Eric Cances, Eleonora Luppi, Julien Toulouse
Summary: This article explores the merits of linear-response range-separated time-dependent density-functional theory (TDDFT) for calculating photoionization spectra. Two variants of range-separated TDDFT are considered and compared with standard methods. The article demonstrates the calculation of photoionization spectra using the Sternheimer approach and applies it to the photoionization spectrum of the Be atom. The results show significant improvement over traditional methods.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Laurens D. M. Peters, Tanner Culpitt, Erik I. Tellgren, Trygve Helgaker
Summary: The Berry curvature plays a crucial role in Born-Oppenheimer molecular dynamics by describing the interaction between electrons and nuclei in a magnetic field. The effective charges derived from the Berry curvature can provide insights into the electronic structure of molecules, allowing for a population analysis. By rewriting the Berry curvature in terms of charges and considering their dependencies on nuclear velocities, a population analysis based on Berry charges and charge fluctuations can be performed, yielding atomic charges and overlap populations. Comparisons with atomic polar tensors demonstrate the usefulness of the Berry population analysis in analyzing electronic structures of molecules.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Erik I. Tellgren, Tanner Culpitt, Laurens D. M. Peters, Trygve Helgaker
Summary: A semiclassical theory for small oscillations in nuclei subject to velocity-dependent forces is presented. The effects of strong magnetic fields on vibrational, rotational, and translational modes are investigated. The theory is developed using both Newtonian mechanics and Hamiltonian formalism, providing insights and quantification of the coupling between different modes. Numerical examples for H-2, HT, and HCN molecules in a strong magnetic field are provided.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Diata Traore, Emmanuel Giner, Julien Toulouse
Summary: The basis-set correction method based on density-functional theory corrects the energy calculated by a wave-function method with a given basis set by a density functional. This method accelerates the convergence of ground-state energies to the complete-basis-set limit by incorporating short-range electron correlation effects missing in the basis set. In this work, the method is extended to a linear-response formalism for calculating excited-state energies, and it is shown to significantly accelerate the basis convergence of excited-state total energies.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Tanner Culpitt, Laurens D. M. Peters, Erik I. Tellgren, Trygve Helgaker
Summary: In an ultrastrong magnetic field, molecular structure and dynamics differ significantly from those on Earth. Nonadiabatic phenomena and processes may play a more important role in this mixed-field regime than in the weak-field regime. The nuclear-electronic orbital (NEO) method is employed to study protonic vibrational excitation energies in the presence of a strong magnetic field, accounting for all terms that result from the nonperturbative treatment.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Sajanthan Sekaran, Oussama Bindech, Emmanuel Fromager
Summary: This study demonstrates the equivalence in one-electron quantum baths between the practical implementation of density matrix embedding theory (DMET) and Householder-transformed density matrix functional embedding theory. Previous research has proven this equivalence in the special case of an idempotent reference full-size density matrix. It is now mathematically proven that this equivalence remains valid even when the density matrix is not idempotent, enabling the construction of correlated quantum baths. A density-matrix functional exactification of DMET is derived within the unified quantum embedding formalism. Numerical examples show that the embedding cluster can be affected by the level of density-matrix functional approximation used for computing the reference density matrix.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Nuclear
Julien Toulouse
Summary: We propose a semiclassical approximation method for calculating photoabsorption cross sections beyond the continuum threshold in quantum many-body systems. The method makes use of the fully quantum-mechanical Wigner function of the ground state and employs semiclassical expansions only for the part of the cross section that depends on the continuum states, avoiding the explicit calculation of these states. The results of testing the method in electronic-structure theory for the photoionization cross sections of hydrogen and helium atoms indicate that these semiclassical approximations can provide good estimates of cross sections at high energy.
EUROPEAN PHYSICAL JOURNAL A
(2023)
Article
Chemistry, Physical
Michiko Atsumi, Jia-Jia Zheng, Erik Tellgren, Shigeyoshi Sakaki, Trygve Helgaker
Summary: This study investigated the adsorption of CO2, acetone, and methanol on UiO-66 using DFT and post-Hartree-Fock calculations. The results showed that UiO-66 can adsorb multiple molecules, and the adsorption capacity and binding energy depend on the type of molecule and adsorption site. NMR spectra were also used to study the adsorption of CO2 on UiO-66.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Mathematics, Interdisciplinary Applications
Sajanthan Sekaran, Matthieu Saubanere, Emmanuel Fromager
Summary: The study establishes a clearer connection between DMET and DFT and shows that a single statically embedded impurity can potentially describe the density-driven Mott-Hubbard transition. Future work will focus on extending LPFET to multiple impurities and generalizing it to quantum chemical Hamiltonians.