A5069997798- Spectroscopy and Quantum Chemical Studies
- Advanced Chemical Physics Studies
- Molecular spectroscopy and chirality
- Photoreceptor and optogenetics research
- Nonlinear Optical Materials Research
- Photochemistry and Electron Transfer Studies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Spectroscopy and Laser Applications
- Nonlinear Optical Materials Studies
- Solid-state spectroscopy and crystallography
- Advanced biosensing and bioanalysis techniques
- Machine Learning in Materials Science
- Protein Structure and Dynamics
- Physics of Superconductivity and Magnetism
- Neural Networks and Applications
- DNA and Nucleic Acid Chemistry
- Computational Physics and Python Applications
- Model Reduction and Neural Networks
- Modular Robots and Swarm Intelligence
- Free Radicals and Antioxidants
- Thermography and Photoacoustic Techniques
- Chemical Thermodynamics and Molecular Structure
- Phase Equilibria and Thermodynamics
- Electrochemical Analysis and Applications
- Crystal Structures and Properties
UiT The Arctic University of Norway
2012-2025
Centre for Arctic Gas Hydrate, Environment and Climate
2020-2024
KTH Royal Institute of Technology
2019-2020
Tromsø research foundation
2016
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 An open‐source program named VeloxChem has been developed for the calculation of electronic real and complex linear response functions at levels Hartree–Fock Kohn–Sham density functional theories. With an object‐oriented structure written in a Python/C++ layered fashion, enables time‐efficient prototyping novel scientific approaches without sacrificing computational efficiency, so that molecular systems involving up to beyond 500 second‐row atoms (or some 10,000 contracted part...
Geometric energy derivatives which rely on core-corrected focal-point energies extrapolated to the complete basis set (CBS) limit of coupled cluster theory with iterative and noniterative quadruple excitations, CCSDTQ CCSDT(Q), are used as elements molecular gradients and, in case expansion coefficients an anharmonic force field. These determine CCSDTQ/CBS CCSDT(Q)/CBS equilibrium structure S0 ground state H2CO where excellent agreement is observed previous work experimentally derived...
We present a second-quantization based Liouville-space formulation of response theory for non-eigenstates unperturbed Hamiltonian in the single-determinant self-consistent field framework, where we include time-independent relaxation superoperator Liouville equation motion. This density-based uses quantities and concepts similar to those introduced established wave function-based forms approximate-state theory, discuss how class relates more general treatment. also various aspects...
We present the first analytic implementation of cubic and quartic force constants at level Kohn–Sham density-functional theory. The is based on an open-ended formalism for evaluation energy derivatives in atomic-orbital basis. relies availability codes one- two-electron integrals differentiated with respect to nuclear displacements as well automatic differentiation exchange–correlation kernels. use generalized second-order vibrational perturbation theory calculate fundamental frequencies...
We present a new implementation of recent open‐ended response theory formulation for time‐ and perturbation‐dependent basis sets (Thorvaldsen et al ., J. Chem. Phys. 2008, 129, 214108) at the Hartree–Fock density functional levels theory. A novel feature is use recursive programming techniques, making it possible to write highly compact code analytic calculation any property valid choice rule order perturbation which include perturbed matrices. The formalism expressed in terms matrix atomic...
We present an implementation of single residues for response functions to arbitrary order using a recursive approach. Explicit expressions in terms density-matrix-based theory the linear, quadratic, cubic, and quartic are also presented. These correspond one-, two-, three- four-photon transition matrix elements. The newly developed code is used calculate absorption cross sections para-nitroaniline para-nitroaminostilbene, making this first treatment framework theory. find that calculated...
Using a recent recursive scheme for the calculation of high-order geometric derivatives molecular properties, we present first analytic calculations infrared and Raman spectra including anharmonicity both in vibrational frequencies IR intensities.
We present the theory and implementation of an open-ended framework for electric response properties that includes effects from molecular environment modeled by polarizable embedding model.
We present a fully analytic approach to calculate infrared (IR) and Raman spectra of molecules embedded in complex molecular environments modeled using the fragment-based polarizable embedding (PE) model. provide theory for calculation second-order geometric derivatives energies first-order electric dipole moments dipole–dipole polarizabilities within PE The are implemented general open-ended response framework, thus allowing an extension higher-order derivatives. embedding-potential...
A class of DNA folds/structures known collectively as G-quadruplexes (G4) commonly forms in guanine-rich areas genomes. G4-DNA is thought to have a functional role the regulation gene transcription and telomerase-mediated telomere maintenance and, therefore, target for drugs. The details molecular interactions that cause stacking guanine-tetrads are not well-understood, which limits rational approach drugability G4 sequences. To explore these interactions, we employed...
We present the first analytic calculations of geometrical gradients hyperpolarizability tensors at density-functional theory (DFT) level. use analytically calculated to explore importance electron correlation effects, as described by DFT, on hyper-Raman spectra. In particular, we calculate spectra all-trans and 11-cis isomers retinal Hartree-Fock (HF) levels theory, also allowing us sensitivity characteristics these structurally related molecules. show that HF results, using B3LYP-calculated...
We present a general approach for the analytic calculation of pure vibrational contributions to molecular (hyper)polarizabilities at density functional level theory. The allows us study large molecules, and we apply new code first dipole hyperpolarizabilities retinal related molecules. investigate importance electron correlation as described by B3LYP exchange-correlation on electronic compare computed with available experimental data. effects corrections vary signficantly even between these...
We present theory, implementation, and applications of a recursive scheme for the calculation single residues response functions that can treat perturbations affect basis set. This enables nonlinear light absorption properties to arbitrary order other than an electric field. apply this first treatment two-photon circular dichroism (TPCD) using London orbitals at Hartree-Fock level theory. In general, TPCD calculations suffer from problem origin dependence, which has so far been solved by...
We present the first computational treatment of complete second-order vibrational perturbation theory applied to hyper-Raman scattering spectroscopy. The required molecular properties are calculated in a fully analytic manner using recently developed program [Ringholm, Jonsson and Ruud, J. Comp. Chem., 2014, 35, 622] that utilizes recursive routines. For some properties, these calculations their kind at respective levels theory. apply this approach calculation spectra methane, ethane...
The study of high-order absorption properties molecules is a field growing importance. Quantum-chemical studies can help design chromophores with desirable characteristics. Given that most experiments are performed in solution, it important to devise cost-effective strategy include solvation effects quantum-chemical these properties. We here present an open-ended formulation self-consistent (SCF) response theory for molecular solute coupled polarizable continuum model (PCM) description the...
Hyper Raman scattering (HRS) of the benzonitrile (BN) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) molecules is studied by means ab initio calculations. The computational procedure employs a recently developed methodology for analytic calculations frequency-dependent polarizability gradients arbitrary order, including perturbation dependent basis sets. result are compared to normal (NRS) coherent anti-Stokes (CARS) that previously have been using same technology. It found some suppressed...
We present the first gauge-origin independent calculations of circular intensity difference (CID) in electric-field-induced second-harmonic generation (EFISHG), including all contributions up to electric-quadrupole–magnetic-dipole level. A recursive, open-ended response theory framework combination with use London atomic orbitals allows us ensure results. apply this approach study EFISHG-CID a collection chiral amino acids. demonstrate that diffuse polarising basis functions are critical...
We present a workflow, benchmarks, and applications to provide roadmap for simulating harmonic IR Raman spectra large solute-solvent systems by employing polarizable-embedding quantum-mechanics (PE-QM) approach. This multiscale modeling scheme divides the system into central core region described quantum-mechanical methods an environment through fragment-based polarizable embedding (PE) model. The workflow involves generating representative structures, calculating properties, post-processing...
ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionCorrection to "Analytic Density-Functional Theory Calculations of Pure Vibrational Hyperpolarizabilities: The First Dipole Hyperpolarizability Retinal and Related Molecules"Bin Gao, Magnus Ringholm, Radovan Bast, Kenneth Ruud*, Andreas J. Thorvaldsen, Michał JaszuńskiCite this: Phys. Chem. A 2014, 118, 15, 2835–2837Publication Date (Web):April 3, 2014Publication History Published online3 April...