A5069996207- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Molecular spectroscopy and chirality
- Laser-Matter Interactions and Applications
- Advanced NMR Techniques and Applications
- Machine Learning in Materials Science
- Photochemistry and Electron Transfer Studies
- History and advancements in chemistry
- X-ray Diffraction in Crystallography
- Spectroscopy and Laser Applications
- Molecular Spectroscopy and Structure
- Crystallography and molecular interactions
- Atmospheric Ozone and Climate
- Molecular Junctions and Nanostructures
- Quantum, superfluid, helium dynamics
- Venous Thromboembolism Diagnosis and Management
- Inorganic Fluorides and Related Compounds
- Electrochemical Analysis and Applications
- Nuclear physics research studies
- Physics of Superconductivity and Magnetism
- Computational Drug Discovery Methods
- Theoretical and Computational Physics
- Fullerene Chemistry and Applications
- Quantum and electron transport phenomena
- Synthesis and Properties of Aromatic Compounds
University of Oslo
2016-2025
Norwegian Academy of Science and Letters
2022-2024
University of Arizona
2024
University of Warsaw
2024
Centre for Advanced Study
2022-2023
Max Planck Institute for the Structure and Dynamics of Matter
2023
Center for Free-Electron Laser Science
2023
Universität Hamburg
2023
UiT The Arctic University of Norway
2008-2023
University of California, Berkeley
2017-2023
Abstract Some of the new unique features MOLCAS quantum chemistry package version 7 are presented in this report. In particular, Cholesky decomposition method applied to some chemical methods is described. This approach used both context a straight forward approximation two‐electron integrals and generation so‐called auxiliary basis sets. The article describes how implemented for most known wave functions models: self‐consistent field, density functional theory, 2nd order perturbation...
In this report, we summarize and describe the recent unique updates additions to M olcas quantum chemistry program suite as contained in release version 8. These include natural spin orbitals for studies of magnetic properties, local linear scaling methods Douglas–Kroll–Hess transformation, generalized active space concept MCSCF methods, a combination multiconfigurational wave functions with density functional theory MC‐PDFT method, additional computation diabatization, analytical gradients...
Dalton is a powerful general-purpose program system for the study of molecular electronic structure at Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, Møller-Plesset, configuration-interaction, and coupled-cluster levels theory. Apart from total energy, wide variety properties may be calculated using these electronic-structure models. Molecular gradients Hessians are available geometry optimizations, dynamics, vibrational studies, whereas magnetic resonance optical...
We demonstrate that substantial computational savings are attainable in electronic structure calculations using a Cholesky decomposition of the two-electron integral matrix. In most cases, effort involved calculating is less than construction one Fock matrix direct O(N2) procedure.
MOLCAS/OpenMolcas is an ab initio electronic structure program providing a large set of computational methods from Hartree-Fock and density functional theory to various implementations multiconfigurational theory. This article provides comprehensive overview the main features code, specifically reviewing use code in previously reported chemical applications as well more recent including calculation magnetic properties optimized matrix renormalization group wave functions.
The electronic structure and low-lying states of a Co(III)(diiminato)(NPh) complex have been studied using multiconfigurational wave function theory (CASSCF/CASPT2). results compared to those obtained with density functional theory. best agreement ab initio is modified B3LYP containing reduced amount (15%) Hartree-Fock exchange. A relativistic basis set 869 functions has employed in the most extensive calculations, where Cholesky decomposition technique was used overcome problems arising...
We propose Cholesky decomposition (CD) of the atomic two-electron integral matrix as a robust and general technique for generating auxiliary basis sets density fitting approximation. The CD (aCD) set is calculated on fly not biased toward particular quantum chemical method. Moreover, accuracy aCD can be controlled with single parameter.
The authors propose a new algorithm, “local K” (LK), for fast evaluation of the exchange Fock matrix in case Cholesky decomposition electron repulsion integrals is used. novelty lies fact that rigorous upper bounds to contribution from each occupied orbital are employed. By formulating these inequalities terms localized orbitals, scaling computing reduced quartic quadratic with only negligible prescreening overhead and strict error control. Compared unscreened computational saving...
Cholesky decomposition of the atomic two-electron integral matrix has recently been proposed as a procedure for automated generation auxiliary basis sets density fitting approximation [F. Aquilante et al., J. Chem. Phys. 127, 114107 (2007)]. In order to increase computational performance while maintaining accuracy, we propose here reduce number primitive Gaussian functions contracted by means second decomposition. Test calculations show that this is most beneficial in conjunction with highly...
Using Cholesky decomposition and density fitting to approximate the electron repulsion integrals, an implementation of complete active space self-consistent field (CASSCF) method suitable for large-scale applications is presented. Sample calculations on benzene, diaquo-tetra-mu-acetato-dicopper(II), diuraniumendofullerene demonstrate that approximations allow larger basis sets systems be treated at CASSCF level theory with controllable accuracy. While strict error control inherent property...
We use Cholesky decomposition of the density matrix in atomic orbital basis to define a new set occupied molecular coefficients. Analysis resulting orbitals ("Cholesky orbitals") demonstrates their localized character inherited from sparsity matrix. Comparison with results traditional iterative localization schemes shows minor differences respect number suitable measures locality, particularly scaling system size pair domains used local correlation methods. The procedure for generating...
Analytical state-average complete-active-space self-consistent field derivative (nonadiabatic) coupling vectors are implemented. Existing formulations modified such that the implementation is compatible with Cholesky-based density fitting of two-electron integrals, which results in efficient calculations especially large basis sets. Using analytical nonadiabatic vectors, optimization conical intersections implemented within projected constrained method. The standard description and...
The Dalton Project provides a uniform platform access to the underlying full-fledged quantum chemistry codes and LSDalton as well PyFraME package for automatized fragmentation parameterization of complex molecular environments. is written in Python defines means library communication interaction. Intermediate data such integrals are exposed made accessible user form NumPy arrays, resulting extracted, analyzed, visualized. Complex computational protocols that may, instance, arise due need...
Abstract Recent years have witnessed an increasing interest in time‐dependent coupled‐cluster (TDCC) theory for simulating laser‐driven electronic dynamics atoms and molecules, molecular vibrational dynamics. Starting from the bivariational principle, we review different flavors of single‐reference TDCC with either orthonormal static, time‐dependent, or biorthonormal spin orbitals. The extension equation‐of‐motion is also discussed, along applications methods to calculation linear absorption...
Deep graph learning based on electronic structure can contribute to the accelerated discovery of transition metal complexes.
We introduce an inherently real coupled cluster time-dependent expectation value of a Hermitian operator. Based on the expansion this in orders generally perturbation, we subsequently identify time-independent value, linear response function, and quadratic function. The functions their residues behave physically correctly. Spectroscopic observables are identified as residues, whereas identification individual transition matrix elements is prohibited. Thus unphysical behavior previously...
A new implementation of the approximate coupled cluster singles and doubles CC2 linear response model using Cholesky decomposition two-electron integrals is presented. Significantly reducing storage demands computational effort without sacrificing accuracy compared to conventional model, algorithm well suited for large-scale applications. Extensive basis set convergence studies are presented static frequency-dependent electric dipole polarizability benzene C60, optical rotation CNOFH2...
The accuracy of auxiliary basis sets derived from Cholesky decomposition two-electron integrals is assessed for excitation energies calculated at the state-average complete active space self-consistent field (CASSCF) and multiconfigurational second order perturbation theory (CASPT2) levels using segmented as well generally contracted atomic orbital sets. Based on 196 valence excitations in 26 organic molecules 72 Rydberg 3 molecules, results show that can be used without compromising...
An analysis of Dunlap's robust fitting approach reveals that the resulting two‐electron integral matrix is not manifestly positive semidefinite when local domains or non‐Coulomb metrics are used. We present a highly approximate method for evaluating four‐center integrals based on resolution‐of‐the‐identity (RI) approximation and apply it to construction Coulomb exchange contributions Fock matrix. In this pair‐atomic (PARI) approach, atomic‐orbital (AO) products expanded in auxiliary...
Abstract At variance, with most of the quantum chemistry software presently available, MOLCAS is a package that specialized in multiconfigurational wave function theory (MC‐WFT) rather than density functional (DFT). Given much higher algorithmic complexity MC‐WFT versus DFT, an extraordinary effort needs to be made from programming point view achieve state‐of‐the‐art performance for large‐scale calculations. In particular, robust and efficient implementation Cholesky decomposition techniques...
Multiconfigurational wavefunction analysis and entanglement measures based on von Neumann entropy shed light the electronic structure of a Ru nitrosyl complex, in particular Ru–NO bond.