0000000000292186

AUTHOR

Wim Klopper

0000-0002-5219-9328

showing 14 related works from this author

Accurate molecular geometries of the protonated water dimer

2000

The equilibrium geometry of the protonated water dimer, H5O2+, was studied using Moller–Plesset perturbation theory and coupled-cluster theory. Constrained geometry optimizations were carried out for the C2 and Cs symmetric structures within the counterpoise framework and near the limit of a complete basis set. In the constrained optimization, the degrees of freedom of the complex are reduced to an intrafragmental distortion and an interfragmental coordinate, making the procedure tractable for large basis sets and explicitly correlated linear r12 methods. The energy of the stationary point of C2 symmetry was found to be 1.2 kJ mol−1 below the energy of the Cs structure.

Water dimerBasis (linear algebra)Ab initio quantum chemistry methodsComputational chemistryChemistryDegrees of freedom (physics and chemistry)General Physics and AstronomyCounterpoiseInteraction energyPhysical and Theoretical ChemistryPerturbation theoryMolecular physicsBasis setPhysical Chemistry Chemical Physics
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Basis-set extrapolation techniques for the accurate calculation of molecular equilibrium geometries using coupled-cluster theory

2006

To reduce remaining basis-set errors in the determination of molecular equilibrium geometries, a basis-set extrapolation (BSE) scheme is suggested for the forces used in geometry optimizations. The proposed BSE scheme is based on separating the Hartree-Fock and electron-correlation contributions and uses expressions obtained by straightforward differentiation of well established extrapolation formulas for energies when using basis sets from Dunning's hierarchy of correlation-consistent basis sets. Comparison with reference data obtained at the R12 coupled-cluster level [CCSD(T)-R12] demonstrates that BSE significantly accelerates the convergence to the basis-set limit, thus leading to impro…

Coupled clusterBasis (linear algebra)Mean squared errorQuantum mechanicsCardinal numberReference data (financial markets)ExtrapolationGeneral Physics and AstronomyApplied mathematicsLimit (mathematics)Physical and Theoretical ChemistryBasis setMathematicsThe Journal of Chemical Physics
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The Dalton quantum chemistry program system

2013

Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, MOller-Plesset, confi ...

Physics::Computational PhysicsPhysicsNuclear TheoryBiochemistryQuantum chemistryComputer Science ApplicationsComputational MathematicsComputational chemistryAb initio quantum chemistry methodsQuantum mechanicsMolecular electronic structurePhysics::Atomic and Molecular ClustersMaterials ChemistryPhysics::Atomic PhysicsPhysics::Chemical PhysicsPhysical and Theoretical ChemistryWiley Interdisciplinary Reviews: Computational Molecular Science
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Single and Multiple Additions of Dibenzoylmethane onto Buckminsterfullerene

2013

A novel dibenzoylmethane-fullerene e,e,e-tris adduct was synthesized by the application of a variation of the Bingel–Hirsch conditions and characterized among others by X-ray crystallography. In addition, the corresponding hexakis adduct was detected by MALDI-TOF-MS analysis. Its existence was supported by density-functional-theory (DFT) computations. Furthermore a new synthesis of bis(benzoyl)methanofullerene was established, and its molecular structure was elucidated by X-ray crystallography. DFT computations reproduced the experimentally determined conformation and predict a low energy barrier for the rotation of the two benzoyl moieties.

FullereneDibenzoylmethane010405 organic chemistryOrganic Chemistry010402 general chemistryMass spectrometry01 natural sciences0104 chemical sciencesAdductchemistry.chemical_compoundLow energyBuckminsterfullerenechemistryComputational chemistryMoleculePhysical and Theoretical ChemistryEuropean Journal of Organic Chemistry
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Basis-set completeness profiles in two dimensions

2002

A two-electron basis-set completeness profile is proposed by analogy with the one-electron profile introduced by D. P. Chong (Can J Chem 1995, 73, 79). It is defined as Y(alpha, beta) = sigmam sigman (Galpha(1)Gbeta(2)/(1/r12)/ psim(1)psin(2)) (psim(1)psin(2)/r12/Galpha(1)Gp(2)) and motivated by the expression for the basis-set truncation correction that occurs in the framework of explicitly correlated methods (Galpha is a scanning Gaussian-type orbital of exponent alpha and [psim] is the orthonormalized one-electron basis under study). The two-electron basis-set profiles provide a visual assessment of the suitability of basis sets to describe electron-correlation effects. Furthermore, they…

Discrete mathematicsComputational MathematicsAngular momentumBasis (linear algebra)TruncationCompleteness (order theory)ExponentGeneral ChemistryExpression (computer science)Linear subspaceBasis setMathematicsJournal of Computational Chemistry
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Erratum: “GW quasiparticle energies of atoms in strong magnetic fields” [J. Chem. Phys. 150, 214112 (2019)]

2019

PhysicsCondensed matter physicsQuasiparticleGeneral Physics and AstronomyPhysical and Theoretical ChemistryMagnetic fieldThe Journal of Chemical Physics
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GW quasiparticle energies of atoms in strong magnetic fields

2019

Quasiparticle energies of the atoms H–Ne have been computed in the GW approximation in the presence of strong magnetic fields with field strengths varying from 0 to 0.25 atomic units (0.25 B 0 =0.25 ℏe −1 a −2 0 ≈58 763 0.25 B0=0.25 ℏe−1a0−2≈58 763 T). The GW quasiparticle energies are compared with equation-of-motion ionization-potential (EOM-IP) coupled-cluster singles-and-doubles (CCSD) calculations of the first ionization energies. The best results are obtained with the evGW@PBE0 method, which agrees with the EOM-IP-CCSD model to within about 0.20 eV. Ionization potentials have been calculated for all atoms in the series, representing the first systematic study of ionization potentials …

PhysicsGW approximation010304 chemical physicsField (physics)General Physics and AstronomyField strengthElectron010402 general chemistry01 natural sciences7. Clean energy0104 chemical sciencesMagnetic fieldIonization0103 physical sciencesPhysics::Atomic and Molecular ClustersQuasiparticlePhysics::Atomic PhysicsPhysical and Theoretical ChemistryAtomic physicsIonization energyThe Journal of Chemical Physics
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Single and Multiple Additions of Dibenzoylmethane onto Buckminsterfullerene (Eur. J. Org. Chem. 35/2013)

2013

chemistry.chemical_compoundBuckminsterfullereneFullerenechemistryDibenzoylmethaneComputational chemistryOrganic ChemistryOrganic chemistryPhysical and Theoretical ChemistryMass spectrometryEuropean Journal of Organic Chemistry
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Explicitly Correlated Electrons in Molecules

2011

Basis set superposition errorQuantum chemistry composite methodsChemistryQuantum mechanicsQuantum Monte CarloPotential energy surfaceMoleculeGeneral ChemistryElectronSTO-nG basis setsChemical Reviews
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CCDC 949721: Experimental Crystal Structure Determination

2014

Related Article: Alexander Giovannitti, Stefan M. Seifermann, Angela Bihlmeier, Thierry Muller, Filip Topic, Kari Rissanen, Martin Nieger, Wim Klopper, and Stefan Bräse|2013|Eur.J.Org.Chem.|2013|7907|doi:10.1002/ejoc.201301146

Space GroupCrystallography1-Hydroxy-3-oxo-13-diphenylprop-1-en-2-yl 4-methylbenzenesulfonateCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
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CCDC 949723: Experimental Crystal Structure Determination

2014

Related Article: Alexander Giovannitti, Stefan M. Seifermann, Angela Bihlmeier, Thierry Muller, Filip Topic, Kari Rissanen, Martin Nieger, Wim Klopper, and Stefan Bräse|2013|Eur.J.Org.Chem.|2013|7907|doi:10.1002/ejoc.201301146

Space GroupCrystallography(bis(benzoyl)methano)-C60fullereneCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
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CCDC 949722: Experimental Crystal Structure Determination

2014

Related Article: Alexander Giovannitti, Stefan M. Seifermann, Angela Bihlmeier, Thierry Muller, Filip Topic, Kari Rissanen, Martin Nieger, Wim Klopper, and Stefan Bräse|2013|Eur.J.Org.Chem.|2013|7907|doi:10.1002/ejoc.201301146

Space GroupCrystallographyCrystal SystemCrystal Structure2-(Dimethylsulfanylidene)-13-diphenylpropane-13-dioneCell ParametersExperimental 3D Coordinates
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CCDC 949720: Experimental Crystal Structure Determination

2014

Related Article: Alexander Giovannitti, Stefan M. Seifermann, Angela Bihlmeier, Thierry Muller, Filip Topic, Kari Rissanen, Martin Nieger, Wim Klopper, and Stefan Bräse|2013|Eur.J.Org.Chem.|2013|7907|doi:10.1002/ejoc.201301146

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parameters2-Bromo-13-diphenylpropane-13-dioneExperimental 3D Coordinates
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CCDC 949724: Experimental Crystal Structure Determination

2014

Related Article: Alexander Giovannitti, Stefan M. Seifermann, Angela Bihlmeier, Thierry Muller, Filip Topic, Kari Rissanen, Martin Nieger, Wim Klopper, and Stefan Bräse|2013|Eur.J.Org.Chem.|2013|7907|doi:10.1002/ejoc.201301146

(bis(benzoyl)methano)-C60fullerene chloroform solvateSpace GroupCrystallographyCrystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
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