The Experts below are selected from a list of 47610 Experts worldwide ranked by ideXlab platform
Michael Dolg - One of the best experts on this subject based on the ideXlab platform.
-
accurate relativistic energy consistent Pseudopotentials for the superheavy elements 111 to 118 including quantum electrodynamic effects
Journal of Chemical Physics, 2012Co-Authors: Tim Hangele, Michael Dolg, Michael Hanrath, Xiaoyan Cao, Peter SchwerdtfegerAbstract:Energy-consistent two-component semi-local Pseudopotentials for the superheavy elements with atomic numbers 111–118 have been adjusted to fully relativistic multi-configuration Dirac–Hartree–Fock calculations based on the Dirac–Coulomb Hamiltonian, including perturbative corrections for the frequency-dependent Breit interaction in the Coulomb gauge and lowest-order quantum electrodynamic effects. The pseudopotential core includes 92 electrons corresponding to the configuration [Xe]4f 145d105f 14. The parameters for the elements 111–118 were fitted by two-component multi-configuration Hartree–Fock calculations in the intermediate coupling scheme to the total energies of 267 up to 797 J levels arising from 31 up to 62 nonrelativistic configurations, including also anionic and highly ionized states, with mean absolute errors clearly below 0.02 eV for averages corresponding to nonrelativistic configurations. Primitive basis sets for one- and two-component pseudopotential calculations have been optimized for t...
-
Quasirelativistic f-in-core Pseudopotentials and core-polarization potentials for trivalent actinides and lanthanides: molecular test for trifluorides
Theoretical Chemistry Accounts, 2010Co-Authors: Anna Weigand, Jun Yang, Michael DolgAbstract:Calibration studies of actinide and lanthanide trifluorides are reported for actinide and lanthanide scalar-relativistic energy-consistent f-in-core Pseudopotentials, respectively, accompanying valence basis sets as well as core-polarization potentials. Results from Hartree–Fock and coupled-cluster singles, doubles, and perturbative triples f-in-core pseudopotential calculations are compared to corresponding data from f-in-valence pseudopotential and all-electron calculations as well as to experimental data. In general, good agreement is observed between the f-in-core and f-in-valence pseudopotential results, whereas due to the lack of experimental data for the actinides only a good agreement of the calculated and experimentally determined bond lengths of the lanthanide systems can be established. Nevertheless, the results indicate that the core-polarization potentials devised here for actinides improve the f-in-core results.
-
energy consistent Pseudopotentials and correlation consistent basis sets for the 5d elements hf pt
Journal of Chemical Physics, 2009Co-Authors: Detlev Figgen, Kirk A Peterson, Michael Dolg, Hermann StollAbstract:New relativistic energy-consistent Pseudopotentials have been generated for the 5d transition metals Hf–Pt. The adjustment was done in numerical two-component multiconfiguration Hartree–Fock calculations, using atomic valence-energy spectra from four-component multiconfiguration Dirac–Hartree–Fock calculations as reference data. The resulting two-component Pseudopotentials replace the [Kr]4d104f14 cores of the 5d transition metals and can easily be split into a scalar-relativistic and a spin-orbit part. They reproduce the all-electron reference energy data with deviations of ∼0.01 eV for configurational averages and ∼0.05 eV for individual relativistic states. Full series of correlation consistent basis sets from double to quintuple-zeta have also been developed in this work for use with the new Pseudopotentials. In addition, all-electron triple-zeta quality correlation consistent basis sets are also reported in order to provide calibration for the pseudopotential treatment. The accuracy of both the pseud...
-
Quasirelativistic energy-consistent 4f-in-core Pseudopotentials for tetravalent lanthanide elements
Theoretical Chemistry Accounts, 2009Co-Authors: Michael Hülsen, Anna Weigand, Michael DolgAbstract:Quasirelativistic energy-consistent 4f-in-core Pseudopotentials modeling tetravalent lanthanides (4f^ n −1 occupation with n = 1, 2, 3, 8, 9 for Ce, Pr, Nd, Tb, Dy) have been adjusted. Energy-optimized (6s5p4d) and (7s6p5d) valence basis sets contracted to polarized double- to quadruple-zeta quality as well as 2f1g correlation functions have been derived. Corresponding smaller (4s4p3d) and (5s5p4d) basis sets suitable for calculations on lanthanide(IV) ions in crystalline solids form subsets of these basis sets designed for calculations on neutral molecules. Calculations for lanthanide tetrafluorides using the 4f-in-core Pseudopotentials at the Hartree–Fock level show satisfactory agreement with calculations using 4f-in-valence Pseudopotentials. For cerium tetrafluoride the experimental bond length is well reproduced using the 4f-in-core pseudopotential at the coupled-cluster level with single and double excitation operators and a perturbative estimate of triple excitations. For cerium dioxide 4f-in-core and 4f-in-valence pseudopotential calculations agree quite well, if a proper f basis set instead of f polarization functions is applied.
-
energy consistent small core Pseudopotentials for 3d transition metals adapted to quantum monte carlo calculations
Journal of Chemical Physics, 2008Co-Authors: M Burkatzki, Claudia Filippi, Michael DolgAbstract:We extend our recently published set of energy-consistent scalar-relativistic Hartree–Fock Pseudopotentials by the 3d-transition metal elements, scandium through zinc. The Pseudopotentials do not exhibit a singularity at the nucleus and are therefore suitable for quantum Monte Carlo (QMC) calculations. The Pseudopotentials and the accompanying basis sets (VnZ with n=T,Q) are given in standard Gaussian representation and their parameter sets are presented. Coupled cluster, configuration interaction, and QMC studies are carried out for the scandium and titanium atoms and their oxides, demonstrating the good performance of the Pseudopotentials. Even though the choice of pseudopotential form is motivated by QMC, these Pseudopotentials can also be employed in other quantum chemical approaches.
Hermann Stoll - One of the best experts on this subject based on the ideXlab platform.
-
energy consistent Pseudopotentials and correlation consistent basis sets for the 5d elements hf pt
Journal of Chemical Physics, 2009Co-Authors: Detlev Figgen, Kirk A Peterson, Michael Dolg, Hermann StollAbstract:New relativistic energy-consistent Pseudopotentials have been generated for the 5d transition metals Hf–Pt. The adjustment was done in numerical two-component multiconfiguration Hartree–Fock calculations, using atomic valence-energy spectra from four-component multiconfiguration Dirac–Hartree–Fock calculations as reference data. The resulting two-component Pseudopotentials replace the [Kr]4d104f14 cores of the 5d transition metals and can easily be split into a scalar-relativistic and a spin-orbit part. They reproduce the all-electron reference energy data with deviations of ∼0.01 eV for configurational averages and ∼0.05 eV for individual relativistic states. Full series of correlation consistent basis sets from double to quintuple-zeta have also been developed in this work for use with the new Pseudopotentials. In addition, all-electron triple-zeta quality correlation consistent basis sets are also reported in order to provide calibration for the pseudopotential treatment. The accuracy of both the pseud...
-
The accuracy of the pseudopotential approximation. III. A comparison between pseudopotential and all-electron methods for Au and AuH
The Journal of Chemical Physics, 2000Co-Authors: Peter Schwerdtfeger, J. Reuben Brown, Jon K. Laerdahl, Hermann StollAbstract:The quality of the pseudopotential approximation has been tested thoroughly by calculating spectroscopic properties of the gold atom and ground state AuH for eight different effective core potentials using Hartree–Fock, second-order Mo/ller–Plesset and coupled cluster methods. The pseudopotential valence basis set {φ}v for Au was chosen to be identical for all Pseudopotentials, a subset of the all-electron basis set {φ}v⊂{φ}AE, and the condition was applied that all sets are of near basis set limit quality. The pseudopotential results are compared with data obtained from nonrelativistic, scalar relativistic Douglas–Kroll and fully relativistic four-component all-electron calculations. The variation between the results obtained for all valence electron small-core Pseudopotentials and all electron Douglas–Kroll calculations is found to be small (for the Stuttgart pseudopotential Δre=0.001 A, ΔDe=0.03 eV, Δωe=9 cm−1, Δμe=0.04 D). Sizable differences to all electron results are only found for the 11 valence e...
-
energy adjusted ab initio Pseudopotentials for the first row transition elements
Journal of Chemical Physics, 1998Co-Authors: Michael Dolg, Hermann Stoll, U Wedig, H PreussAbstract:Nonrelativistic and quasirelativistic ab‐initio Pseudopotentials representing the Ne‐like X(Z−10)+ cores (X=Sc–Zn) of the first row transition metals and optimized (8s7p6d1f )/[6s5p3d1f ]‐GTO valence basis sets for use in molecular calculations have been generated. Excitation and ionization energies of the low lying states of Sc through Zn from numerical HF‐ as well as SCF‐ and CI(SD)‐pseudopotential calculations using the derived basis sets differ by less than 0.1 eV from corresponding all‐electron results.
-
the accuracy of the pseudopotential approximation ii a comparison of various core sizes for indium Pseudopotentials in calculations for spectroscopic constants of inh inf and incl
Journal of Chemical Physics, 1996Co-Authors: Thierry Leininger, Hermann Stoll, Michael Dolg, Andreas Nicklass, Peter SchwerdtfegerAbstract:Small‐ and medium‐core Pseudopotentials representing [Ar]3d10‐ and [Kr]‐like cores, respectively, have been adjusted for the In atom, supplementing the energy‐consistent three‐valence‐electron large‐core ([Kr]4d10 core) pseudopotential of the Stuttgart group. The performance of these potentials is tested against those of other groups and against experiment, in calculations for the ground‐state potential curves of InH, InF, and InCl, both at the self‐consistent‐field and correlated levels. The role of the core size is discussed, and systematic errors of large‐ and medium‐core Pseudopotentials are analyzed.
-
relativistic and correlation effects for element 105 hahnium ha a comparative study of m and mo m nb ta ha using energy adjusted ab initio Pseudopotentials
The Journal of Physical Chemistry, 1993Co-Authors: Michael Dolg, Hermann Stoll, H Preuss, Russell M PitzerAbstract:Nonrelativistic and quasirelativistic energy-adjusted ab initio Pseudopotentials are presented for element 105 (hahnium, Ha) together with corresponding energy-optimized valence basis sets. The method of energy adjustment of Pseudopotentials is extended to a two-component formalism and to multiconfiguration wave functions. The accuracy of the pseudopotential scheme is demonstrated by a comparison of atomic valence-only results to corresponding all-electron data. Atomic multiconfiguration self-consistent field and multireference configuration interaction calculations for M and M[sup +] (M = Nb, Ta, Ha) are compared with available experimental data. Corresponding molecular calculations, which included spin-orbit coupling, have been performed for the low-lying states of HaO and are compared to the results from corresponding calculations of the lighter homologs NbO and TaO. 41 refs., 1 fig., 8 tabs.
Emily A. Carter - One of the best experts on this subject based on the ideXlab platform.
-
globally optimized local Pseudopotentials for orbital free density functional theory simulations of liquids and solids
Journal of Chemical Theory and Computation, 2017Co-Authors: Beatriz G Del Rio, Johannes M Dieterich, Emily A. CarterAbstract:The accuracy of local Pseudopotentials (LPSs) is one of two major determinants of the fidelity of orbital-free density functional theory (OFDFT) simulations. We present a global optimization strategy for LPSs that enables OFDFT to reproduce solid and liquid properties obtained from Kohn–Sham DFT. Our optimization strategy can fit arbitrary properties from both solid and liquid phases, so the resulting globally optimized local Pseudopotentials (goLPSs) can be used in solid and/or liquid-phase simulations depending on the fitting process. We show three test cases proving that we can (1) improve solid properties compared to our previous bulk-derived local pseudopotential generation scheme; (2) refine predicted liquid and solid properties by adding force matching data; and (3) generate a from-scratch, accurate goLPS from the local channel of a non-local pseudopotential. The proposed scheme therefore serves as a full and improved LPS construction protocol.
-
Ultrasoft spin-dependent Pseudopotentials.
The Journal of chemical physics, 2005Co-Authors: Vincent Cocula, Chris J. Pickard, Emily A. CarterAbstract:The use of the spin-dependent Pseudopotentials has been shown to markedly enhance the transferability of the commonly used spin-neutral pseudopotential method for the study of the structural and magnetic properties of transition-metal-containing materials. Unfortunately, because the method was based on the rather expensive norm-conserving pseudopotential formalism, the method was limited to the study of fairly small systems. Here we present an extension of the spin-dependent pseudopotential method for the far more computationally advantageous ultrasoft formalism and show that it is very easy to add such a feature to any preexisting computer code. We benchmark our new method by comparing to previously published results and then apply it to the study of several relevant test cases: bulk Ni, Fe, and Co, as well as a Pd atomic wire.
-
Breakdown of the pseudopotential approximation for magnetic systems: Predicting magnetic quenching at the V(001) surface with spin-dependent Pseudopotentials
Physical Review B, 2004Co-Authors: Vincent Cocula, Emily A. CarterAbstract:Both experimentally [R.L. Fink et al., Phys. Rev. B 41, 10 175 (1990)] and using all-electron density-functional theory (DFT) method, the V(001) surface exhibits little or no magnetization. Very recently, independent pseudopotential DFT calculations demonstrated the breakdown of the pseudopotential approximation, showing large magnetic moments at the surface of a V(001) slab. Here we demonstrate that use of spin-dependent Pseudopotentials systematically corrects the inaccuracies of conventional spin-neutral Pseudopotentials, producing results consistent with all-electron ones. We also show how the use of the spin-dependent Pseudopotentials allows one to achieve a high level of accuracy without the numerical difficulties and cost associated with accurate spin-neutral Pseudopotentials.
Jürg Hutter - One of the best experts on this subject based on the ideXlab platform.
-
Soft norm-conserving pseudopotential for carbon
The European Physical Journal B, 2000Co-Authors: A. Šimůnek, Jiří Vackář, Karel Kunc, Jürg HutterAbstract:A soft, norm-conserving pseudopotential for carbon is presented and its performance tested by calculations on atomic states and on diamond: electronic energy levels of different atomic configurations, equilibrium lattice constant, bulk modulus, and the TA(X) frozen-phonon frequency are accurately reproduced. Convergence of the total energy of diamond with the size of the plane-wave basis set is compared for several frequently used Pseudopotentials, and it is shown that calculations with the reported pseudopotential can be performed at considerably lower cost than with the other norm-conserving Pseudopotentials, without loosing the accuracy of the latter in predicting structural and dynamical properties. The rapid convergence of the results with the plane-wave cutoff is comparable to the performance of the Vanderbilt's ultrasoft Pseudopotentials. The transferability of the pseudopotential to other electronic configurations is discussed.
-
relativistic separable dual space gaussian Pseudopotentials from h to rn
Physical Review B, 1998Co-Authors: C Hartwigsen, Stefan Goedecker, Jürg HutterAbstract:We generalize the concept of separable dual-space Gaussian Pseudopotentials to the relativistic case. This allows us to construct this type of pseudopotential for the whole Periodic Table, and we present a complete table of pseudopotential parameters for all the elements from H to Rn. The relativistic version of this pseudopotential retains all the advantages of its nonrelativistic version. It is separable by construction, it is optimal for integration on a real-space grid, it is highly accurate, and, due to its analytic form, it can be specified by a very small number of parameters. The accuracy of the pseudopotential is illustrated by an extensive series of molecular calculations.
-
Separable dual-space Gaussian Pseudopotentials
Physical review. B Condensed matter, 1996Co-Authors: Stefan Goedecker, M. P. Teter, Jürg HutterAbstract:We present pseudopotential coefficients for the first two rows of the Periodic Table. The pseudopotential is of an analytic form that gives optimal efficiency in numerical calculations using plane waves as a basis set. At most, seven coefficients are necessary to specify its analytic form. It is separable and has optimal decay properties in both real and Fourier space. Because of this property, the application of the nonlocal part of the pseudopotential to a wave function can be done efficiently on a grid in real space. Real space integration is much faster for large systems than ordinary multiplication in Fourier space, since it shows only quadratic scaling with respect to the size of the system. We systematically verify the high accuracy of these Pseudopotentials by extensive atomic and molecular test calculations. \textcopyright{} 1996 The American Physical Society.
H Preuss - One of the best experts on this subject based on the ideXlab platform.
-
energy adjusted ab initio Pseudopotentials for the first row transition elements
Journal of Chemical Physics, 1998Co-Authors: Michael Dolg, Hermann Stoll, U Wedig, H PreussAbstract:Nonrelativistic and quasirelativistic ab‐initio Pseudopotentials representing the Ne‐like X(Z−10)+ cores (X=Sc–Zn) of the first row transition metals and optimized (8s7p6d1f )/[6s5p3d1f ]‐GTO valence basis sets for use in molecular calculations have been generated. Excitation and ionization energies of the low lying states of Sc through Zn from numerical HF‐ as well as SCF‐ and CI(SD)‐pseudopotential calculations using the derived basis sets differ by less than 0.1 eV from corresponding all‐electron results.
-
relativistic and correlation effects for element 105 hahnium ha a comparative study of m and mo m nb ta ha using energy adjusted ab initio Pseudopotentials
The Journal of Physical Chemistry, 1993Co-Authors: Michael Dolg, Hermann Stoll, H Preuss, Russell M PitzerAbstract:Nonrelativistic and quasirelativistic energy-adjusted ab initio Pseudopotentials are presented for element 105 (hahnium, Ha) together with corresponding energy-optimized valence basis sets. The method of energy adjustment of Pseudopotentials is extended to a two-component formalism and to multiconfiguration wave functions. The accuracy of the pseudopotential scheme is demonstrated by a comparison of atomic valence-only results to corresponding all-electron data. Atomic multiconfiguration self-consistent field and multireference configuration interaction calculations for M and M[sup +] (M = Nb, Ta, Ha) are compared with available experimental data. Corresponding molecular calculations, which included spin-orbit coupling, have been performed for the low-lying states of HaO and are compared to the results from corresponding calculations of the lighter homologs NbO and TaO. 41 refs., 1 fig., 8 tabs.
-
accuracy of energy adjusted quasirelativistic ab initio Pseudopotentials
Molecular Physics, 1993Co-Authors: U Haussermann, Hermann Stoll, Michael Dolg, Peter Schwerdtfeger, H Preuss, Russell M PitzerAbstract:The results of valence-only self-consistent field calculations on Hg n+ (n = 0, 1, 2) and HgH n+ (n = 0, 1) using nonrelativistic and quasirelativistic energy-adjusted ab initio Pseudopotentials for Hg are compared with corresponding all-electron values from nonrelativistic (Hartree-Fock) and relativistic (Dirac-Fock) atomic as well as from nonrelativistic (Hartree-Fock) and quasirelativistic (Hartree-Fock with no-pair Hamiltonian) molecular calculations. The accuracy of the energy-adjusted ab initio pseudopotential scheme, e.g., the reproduction of the major relativistic effects, is demonstrated both for the atom and the molecule. Correlation effects are included in the quasirelativistic pseudopotential studies by means of large-scale configuration interaction calculations. The quasirelativistic pseudopotential results obtained in the intermediate coupling scheme are in excellent agreement with available experimental data.
-
ab initio Pseudopotentials for hg through rn
Molecular Physics, 1991Co-Authors: Wolfgang Kuchle, Hermann Stoll, Michael Dolg, H PreussAbstract:Quasirelativistic and nonrelativistic energy adjusted ab initio Pseudopotentials for the elements Hg through Rn are presented together with corresponding optimized valence basis sets. Core-valence correlation is accounted for by semiempirical polarization potentials. Corrections to the point charge repulsion in the core-nucleus interaction for subsequent molecular calculations are also provided. The reliability of the pseudopotential method is demonstrated in atomic test calculations for electron affinities, excitation and ionization energies as well as spin-orbit splittings by comparison with nonrelativistic, quasirelativistic and relativistic all-electron data. Results obtained by means of two quasirelativistic configuration interaction schemes that include spin-orbit coupling are compared with experimental data.
