0000000000413356

AUTHOR

Markus Reiher

0000-0002-9508-1565

showing 3 related works from this author

Nuclear Quadrupole Moment of 119Sn

2008

Second-order scalar-relativistic Douglas-Kroll-Hess density functional calculations of the electric field gradient, including an analytic correction of the picture change error, were performed for 34 tin compounds of which molecular structures and Sn-119 Mossbauer spectroscopy parameters are experimentally known. The components of the diagonalized electric field gradient tensor, V-xx,V-yy, V-zz, were used to determine the quantity V, which is proportional to the nuclear quadrupole splitting parameter Delta E. The slope of the linear correlation plot of the experimentally determined Delta E parameter versus the corresponding calculated V data allowed us to obtain an absolute value of the nuc…

Mössbauer spectroscopyrelativistic effectAnalytical chemistrychemistry.chemical_elementAbsolute valueQuadrupole splittingelectric field gradientchemistryCore electronSettore CHIM/03 - Chimica Generale E InorganicaElectric fieldtinQuadrupolePhysical and Theoretical ChemistryAtomic physicsTinElectric field gradientBasis setnuclear quadrupole splitting
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OpenMolcas: From Source Code to Insight

2019

In this article we describe the OpenMolcas environment and invite the computational chemistry community to collaborate. The open-source project already includes a large number of new developments realized during the transition from the commercial MOLCAS product to the open-source platform. The paper initially describes the technical details of the new software development platform. This is followed by brief presentations of many new methods, implementations, and features of the OpenMolcas program suite. These developments include novel wave function methods such as stochastic complete active space self-consistent field, density matrix renormalization group (DMRG) methods, and hybrid multico…

Wave functionSource codeField (physics)Computer sciencemedia_common.quotation_subjectInterfacesSemiclassical physics010402 general chemistry0601 Biochemistry and Cell Biology01 natural sciencesComputational scienceNOChemical calculationsMathematical methodschemical calculations ; electron correlation ; interfaces ; mathematical methods ; wave function0103 physical sciences0307 Theoretical and Computational ChemistryPhysical and Theoretical ChemistryWave functionWave function Interfaces Chemical calculations Mathematical methods Electron correlationComputingMilieux_MISCELLANEOUSmedia_commonChemical Physics010304 chemical physicsBasis (linear algebra)business.industryDensity matrix renormalization groupElectron correlationSoftware development0803 Computer Software0104 chemical sciencesComputer Science ApplicationsVisualization[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistrybusiness
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Analytic high-order Douglas–Kroll–Hess electric field gradients

2007

In this work we present a comprehensive study of analytical electric field gradients in hydrogen halides calculated within the high-order Douglas-Kroll-Hess (DKH) scalar-relativistic approach taking picture-change effects analytically into account. We demonstrate the technical feasibility and reliability of a high-order DKH unitary transformation for the property integrals. The convergence behavior of the DKH property expansion is discussed close to the basis set limit and conditions ensuring picture-change-corrected results are determined. Numerical results are presented, which show that the DKH property expansion converges rapidly toward the reference values provided by four-component met…

Classical mechanicsChemistryOperator (physics)Convergence (routing)General Physics and AstronomyApplied mathematicsUnitary matrixLimit (mathematics)Perturbation theory (quantum mechanics)Physical and Theoretical ChemistryUnitary transformationParametrizationBasis set
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