Center for Molecular Modeling - K. Koepernik

Reproducibility in density functional theory calculations of solids

kurt — Mon, 14 Sep 2015 18:32:04 +0000

K. Lejaeghere, G. Bihlmayer, T. Björkman, P. Blaha, S. Blügel, V. Blum, D. Caliste, I.E. Castelli, S.J. Clark, A. Dal Corso, S. de Gironcoli, T. Deutsch, J.K. Dewhurst, I. Di Marco, C. Draxl, M. Dułak, O. Eriksson, J.A. Flores-Livas, K.F. Garrity, L. Genovese, P. Giannozzi, M. Giantomassi, S. Goedecker, X. Gonze, O. Grånäs, E.K.U. Gross, A. Gulans, F. Gygi, D.R. Hamann, P.J. Hasnip, N.A.W. Holzwarth, D. Iușan, D.B. Jochym, F. Jollet, D. Jones, G. Kresse, K. Koepernik, E. Küçükbenli, Y.O. Kvashnin, I.L.M. Locht, S. Lubeck, M. Marsman, N. Marzari, U. Nitzsche, L. Nordström, T. Ozaki, L. Paulatto, C.J. Pickard, W. Poelmans, M.I.J. Probert, K. Refson, M. Richter, G.-M. Rignanese, S. Saha, M. Scheffler, M. Schlipf, K. Schwarz, S. Sharma, F. Tavazza, P. Thunström, A. Tkatchenko, M. Torrent, D. Vanderbilt, M.J. van Setten, V. Van Speybroeck, J.M. Wills, J.R. Yates, G.-X. Zhang, S. Cottenier

Science

351 (6280), 1415-aad3000-7

2016

Abstract

The widespread popularity of density functional theory has given rise to an extensive range of dedicated codes for predicting molecular and crystalline properties. However, each code implements the formalism in a different way, raising questions about the reproducibility of such predictions. We report the results of a community-wide effort that compared 15 solid-state codes, using 40 different potentials or basis set types, to assess the quality of the Perdew-Burke-Ernzerhof equations of state for 71 elemental crystals. We conclude that predictions from recent codes and pseudopotentials agree very well, with pairwise differences that are comparable to those between different high-precision experiments. Older methods, however, have less precise agreement. Our benchmark provides a framework for users and developers to document the precision of new applications and methodological improvements.

DOI

http://dx.doi.org/10.1126/science.aad3000

Private attachment

aad3000.full_.pdf

article-Delta-scifile-with-tables.pdf

Electron penetration into the nucleus and its effect on the quadrupole interaction

wim — Tue, 13 Sep 2011 12:49:39 +0000

K. Koch, K. Koepernik, D. Van Neck, H. Rosner, S. Cottenier

Physical Review A

81, 032507

2010

Abstract

series expansion of the interaction between a nucleus and its surrounding electron distribution provides terms that are well-known in the study of hyperfine interactions: the familiar quadrupole interaction and the less familiar hexadecapole interaction. If the penetration of electrons into the nucleus is taken into account, various corrections to these multipole interactions appear. The best known correction is a scalar term related to the isotope shift and the isomer shift. This paper discusses a related tensor correction, which modifies the quadrupole interaction if electrons penetrate the nucleus: the quadrupole shift. We describe the mathematical formalism and provide first-principles calculations of the quadrupole shift for a large set of solids. Fully relativistic calculations that explicitly take a finite nucleus into account turn out to be mandatory. Our analysis shows that the quadrupole shift becomes appreciably large for heavy elements. Implications for experimental high-precision studies of quadrupole interactions and quadrupole moment ratios are discussed. A literature review of other small quadrupole-like effects is presented as well (pseudoquadrupole effect, isotopologue anomaly, etc.).

Open Access version available at UGent repository

DOI

http://dx.doi.org/10.1103/PhysRevA.81.032507

Private attachment

10 phys. rev. A 81(3)032507 koch.pdf

A new challenge to molecular spectroscopy: The quadrupole shift as a second order correction to the isomer shift

wim — Mon, 17 Oct 2011 13:43:21 +0000

K. Koch, H. Rosner, D. Van Neck, K. Koepernik, S. Cottenier

Poster

Conference / event / venue

High Resolution Molecular Spectroscopy 2009

Castellamare di Stabia, Italy

Tuesday, 31 August, 2010 to Saturday, 4 September, 2010

Electron penetration into the nucleus and its effect on the quadrupole interaction

wim — Mon, 17 Oct 2011 13:32:37 +0000

K. Koch, H. Rosner, K. Koepernik, D. Van Neck, S. Cottenier

P. 226

Poster

Conference / event / venue

Psi-k Conference

Berlin, Germany

Sunday, 12 September, 2010 to Thursday, 16 September, 2010

Abstract

Psi-k-2010-abstract-quadrupole-shift.pdf

Conference reference

Psi-k Conference 2010

Electron penetration into the nucleus and its effect on the quadrupole interaction

wim — Mon, 17 Oct 2011 08:41:54 +0000

K. Koch, K. Koepernik, D. Van Neck, S. Cottenier

Talk

Conference / event / venue

3rd Joint International Conference on Hyperfine Interactions and International Symposium on Nuclear Quadrupole Interactions

CERN, Geneva, Switzerland

Monday, 13 September, 2010 to Friday, 17 September, 2010

Abstract

abstract HFI 2010 Geneva - quadrupole shift.pdf