Samuel B. Trickey

This web site is kept mostly for historical reasons and updated only occasionally. To keep up with our research progress on free-energy density functional theory (DFT) and orbital-free DFT, please go to the project website .

Personal Information
  • Professor of Physics and Chemistry (emeritus June 2005)
  • Former Director QTP (1999-2004)
  • Email address: trickey at qtp dot ufl dot edu
  • Office: 2324 New Physics Building
  • Phone: 352-392-6978
  • Fax: 352-392-8722

13 May 2020: We have a new postdoc position available. Go to the project website for further information.

Research Interests

Center for Molecular Magnetic Quantum Materials

I am a co-PI in the Center, working mostly on algorithms and on spin-crossover molecules and assemblies of them. Much more information is available from the the Center website .

Density Functional Theory

I work on DFT, both ground state and free-energy (finite temperature) versions, and to some extent on Current DFT (CDFT).

Since Sept. 2009, we have had a major Dept. of Energy project for development of orbital-free free-energy density functionals. Target physical systems are in the Warm Dense Matter regime: typical electron temperatures are of order 10 electron volts yet at condensed-phase densities. The original co-PIs were Jim Dufty, Frank Harris, and Keith Runge. The project is a major development of earlier zero-temprature work with Valentin Karasiev (formerly of IVIC, Venezuela, now Lab. for Laser Energetics, Univ. of Rochester) and Frank Harris on developing orbital-free approximations to the Kohn-Sham kinetic energy to use in calculating Born-Oppenheimer forces in fast molecular dynamics simulations. See references below

Recently (May 2020) I received a National Science Foundation grant with Antonio Cancio, Ball State Univ as co-PI, for "Pure Density Functionals for Efficient, Predictive Simulations". It is a follow-on to success with a NSF EAGER grant "Rung-reduced Density Functionals for Cost-capped ab initio Molecular Dynamics" which demonstrated the concept of de-orbitalization of metaGGA exchange-correlation functionals.

That work is closely related to the continuting collaboration with Alberto Vela ( Cinvestav, Mexico City) and José Luis Gázquez (UAM-I, Mexico City) and their associates, notably Javier Carmona Espíndola at UAM-I. We have been pushing the limits of the lower rungs of the Perdew-Schmidt "Jacob's ladder" of exchange- correlation functionals. Publications for the last decade are at the Publications page of my group's web site.

Wuming Zhu (Ph.D. August 2005) and I from time to time work on Current DFT. We introduced a self-interaction-free ordinary DFT treatment of atoms in large external B fields. Remarkably, current DFT isn't needed. See the Phys. Rev. A 90 paper listed in the publications or get it from Publications

Development of Algorithms for Predictive Simulations of Materials

PUPIL (Program for User Package Interfacing and Linking) is an open-source JAVA, CORBA, and XML-based system for interoperating user application packages (e.g. electronic structure, molecular dynamics, domain identifiers) as a systematic multi-scale modeling tool. Begun under the NSF ITR-medium award (DMR-0325553), development now is with Joan Torras Costa. Earlier the development group was Joan, Erik Deumens, Gustavo Seabra, Ben Roberts, and I. There is a bio-molecular oriented review cited in the publication list below. Also see the project link .

Gaussian-basis, all-electron methods and algorithm for detailed DFT calculations on materials were developed in close collaboration with Jon Boettger (LANL, now retired), the principal author of the code GTOFF (that originated here). A review article is listed below.

For several years I also worked on adding features and functionality to the deMon2k molecular, Gaussian basis DFT code, in cooperation with the development group at Cinvestav, Mexico City. The deMon2k home page is here . For lack of time I have not done that recently.



Older Representative Publications
  • Please see above for Publications links to the group web site.
  • Scaling, Bounds, and Inequalities for the Non-interacting Density Functionals at Finite Temperature, J.W. Dufty and S.B. Trickey, Phys. Rev. B; accepted 06 July 2011; arXiv 1105.2276v1.
  • Positivity Constraints and Information-theoretical Kinetic Energy Functionals, S.B. Trickey, V.V. Karasiev, and A. Vela, Phys. Rev. B 84, 075146 [7 pp] (2011).
  • Constraint-based Single-point Approximate Kinetic Energy Functionals, V.V. Karasiev, R.S. Jones, S.B. Trickey, and F.E. Harris, Phys. Rev. 80, 245120 [17 pp] (2009).
  • Variable Lieb-Oxford Bound Satisfaction in a Generalized Gradient Exchange-Correlation Functional, A. Vela, V. Medel and S. B.Trickey, J. Chem. Phys. 130, 244103 [6 pp] (2009).
  • Tightened Lieb-Oxford Bound for Systems of Fixed Particle Number, M.M. Odashima, K. Capelle, and S.B.Trickey, J. Chem. Theory and Comput. 5, 798-807 (2009).
  • A Versatile AMBER-Gaussian QM/MM Interface Through PUPIL, J. Torras, G. de M. Seabra, E. Deumens, S.B. Trickey, and A.E. Roitberg, J. Comput. Chem. 29, 1564-1573 (2008).
  • PUPIL: A Systematic Approach to Software Integration in Multi-scale Simulations , J. Torras, Y. He, C. Cao, K. Muralidharan, E. Deumens, H-P. Cheng, and S.B. Trickey, Computer Phys. Commun. 177, 265-79 (2007).
  • First Principles Calculation of Spin-orbit Splitting in Graphene , J.C. Boettger and S.B.Trickey, Phys. Rev. B 75, 121402(R) [3 pp] (2007); erratum Phys. Rev. B 75, 199903 (2007). .
  • Exact Density Functionals for Two-electron Systems in an External Magnetic Field , Wuming Zhu and S.B. Trickey, J. Chem. Phys. 125, 094317 [12 pp] (2006).
  • Methods and Implementation of Robust, High-precision Gaussian Basis DFT Calculations for Periodic Systems: the GTOFF Code, S. B. Trickey, J. A. Alford, and J. C. Boettger, in Computational Materials Science, vol. 15 of "Theoretical and Computational Chemistry", J.Leszczynski ed. (Elsevier, Amsterdam, 2004) 171-228.
  • State Energy Functionals and Variational Equations in Density Functional Theory, B. Weiner and S. B. Trickey, J. Molec. Struct. (Theochem) 501-02, 65-83 (2000).
  • A Critical Assessment of Density Functional Theory with Regard to Applications in Organometallic Chemistry, A. Görling, S.B. Trickey, P. Gisdakis, and N. Rösch, in Topics in Organometallic Chemistry, vol. 4, P. Hofmann and J.M. Brown, Eds. (Springer Verlag, Heidelberg, 1999) 109-63.
Click here for a more extensive list of Publications through 2015. (Thanks to Richard Mathar for the massive update.)

Invited Lectures - an Older Sample

  • Coherent Approach to Orbital-free DFT, FCAM Workshop ``The Orbital-free Alternative'', Institut Henri Poincaré, Paris, 30-31 May 2011.
  • Consistent Orbital-free DFT: Stalking an Ancient Prey , Université Pierre et Marie Curie (Paris 6), Laboratoire de Chimie Théorique, Jussieu, 01 June 2011.
  • New Approaches to Old Ideas, Workshop on New Approaches to Many Electron Theory, organized by Mathematics Dept. Technische Universität Mainz and Max Planck Institut für Polymerforschung, Mainz Germany, 19 Sept. 2010.
  • Reworking the Second Rung of the Exchange-Correlation Ladder, Symposium on Density Functional Methods and Their Applications, Geburtstagfest für Prof. N. Rösch, Technische Universität München, 7 Nov. 2008.
  • Tightening the Lieb-Oxford Bound in the PBE Exchange-Correlation Functional , Simposio de Teoría de Funcionales de la Densidad, Univ. Autónoma Metropolitana -- Iztapalapa, México City, México, 17 October 2008.
  • Física de Música y Música de Física, (in Spanish) Escuela de Laudería, Instituto Nacion&aacut;el de Bellas Artes de México, Querétaro, Querétaro, México, 14 October 2008.
  • Short Course on Density Functional Theory and Applications , 10 lectures, Dept. of Physics, Michigan Technological University, Houghton Michigan, Sept. 15--19, 2008.
  • Recent Progress on Orbital-free Kinetic Energy Density Functionals for Materials Simulations , Sixth Congress of the Internat. Soc. for Theoretical Chemical Physics, Vancouver B.C., 24 July 2008

Chile Click here for 2005 visit to Chile.

Here's the link to National Farm Worker Ministry, a long-time personal commitment.
Here's the link to the Gainesville sailing club

Last modified 31 May 2020