Stefano de Gironcoli

E-mail

 degironc (at) sissa.it

Office

 A 405

Web

 http://people.sissa.it/~degironc

Tel

 +39 040 3787 433

Fax

 +39 040 3787 249

Vita

Stefano de Gironcoli, born in 1964, was appointed associate professor of theoretical condensed-matter physics at SISSA in 2001, where he was assistant professor (ricercatore) since 1994. SdG obtained a docteur es science (PhD) degree at the Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne (CH), in 1992 and spent one year as a post-doc at the Scuola Normale Superiore (SNS) in Pisa.
Since 2009, he’s the Director of the DEMOCRITOS Simulation Centre, the theory branch of the Istituto Officina dei Materiali (IOM) of the Italian National Research Council (CNR).

Research

SdG’s research interests include application of atomistic simulations and electronic structure methods to surface science, theoretical heterogeneous catalysis, description of dispersion interaction in physisorption and molecular solids, vibrational properties and their influence on structural and thermodynamical properties of materials, vibrational and NMR spectroscopy, treatment of non-local exchange effects in transition metal oxides and other correlated materials. A very important part of SdG’s research activity involves the development and optimization of electronic structure methods for numerical simulations of matter at the nanoscale, notably in the Quantum ESPRESSO suite of codes (www.quantum-espresso.org) of which he’s one of the long term active developers.

Current active research lines:

  1. understanding reactivity at the nanoscale
    Environmentally friendly production of alternative fuels and basic chemicals, such as low temperature methanol or ammonia synthesis, improved efficiency in exhaust gas purification, such as selective oxidation of carbon or nitrogen monoxide, or enhanced selectivity of important chemical processes, such as the partial oxidation of ethylene to its epoxyde, are among the topics that have been studied and are of current interest, with particular focus on the role played by the local chemical environment, undercoordination, strain on adsorption properties and reactivity. In this contest we can mention a fruitful collaboration with A. Baraldi and coworkers at the Elettra superESCA beamlin that, with a combined experimental (XPS) and theoretical (DFT) approach, has demonstrated the ability to monitor the effect of local chemical and geometrical environment on core-level binding energy shifts of surface atoms and adsorbates.
  2. Addressing shortcomings of current exchange-correlation functionals
    In spite of their many and well recognized successes, standard LDA/GGA methods in Density Functional Theory meet difficulties and even badly fail in a number of critically important situations.
    One of the most spectacular failure of LDA/GGA approaches is the incorrect metallic description of many transition metal or rare earth oxides, while they are Mott-type insulators experimentally. A few years ago, we readdressed the problem by defining the     DFT+U approach, originally introduces by Anisimov and coworkers in the ‘90, in terms of general projectors devising an internally consistent way to compute U from first-principles. This development has been instrumental in initiating an activity, now pursued by Dr. S. Fabris at the DEMOCRITOS Simulation Centre of IOM-CNR, on highly-active catalysts based on metal nano-particles (Au, Pt, Rh, Pd) supported by reducible metal oxides, such as cerium oxides (ceria), where the presence of localized f-electrons calls for a special treatment. In collaboration with R.M. Wentzcovitch (UMN, Minneapolis) a systematic study of the thermoelastic properties of candidate mineral phases in Earth’s lower mantle is underway. Iron content in lower mantle minerals is estimated to be 10-20 % and its theoretical treatment requires again special care.
    Another spectacular failure of standard LDA/GGA approximations is their inability, due to their intrinsic local nature, to describe dispersion ( van der Waals    ) interaction between non overlapping molecular fragments, and, what is more relevant for catalysis, weakly bound systems such as molecules about to break during a chemical reaction. This is a topic of current great interest and we are working in two directions: i) efficiently implementing and testing in a number of systems new fully non-local functionals that have been proposed, and ii) tackling the problem at the very fundamental level starting from the Adiabatic Coupling Fluctuation Dissipation (ACFD) formalism and working to obtain an accurate value of the RPA correlation energy (and its scf potential) via eigenvalue decomposition of the non-interacting response function of the system, obtained efficiently via density functional perturbation theory. RPA and its exchange-including generalization (SOSEX) are currently proposed as a (very expensive) systematic improvement on current functionals and their efficient calculation is highly desirable.
  3. Further software and theoretical developments
    In addition to the above, I’m in general very interested in methodological/theoretical developments and in their actual implementation in the computational engine that lies at the core of all the simulations we are performing or may wish to perform in the future, namely into the Quantum ESPRESSO package. In particular I’m deeply interested in developments that can enhance the overall accuracy of the calculations we can perform.
    In this context, I’ve coordinated the implementation of Bloechl’s Projector Augmented Waves (PAW) formalism in Quantum ESPRESSO. This effort allow us now, and the scientific community utilizing these codes, to perform all-electron calculations with the efficiency typical of a plane-wave pseudopotential approach. The effort is continuing now fostering the development of PAW dataset for elements of the whole periodic table and in accumulating and organizing all-electron reference calculations in collaboration with colleagues having significant all electron expertieses (S. Massidda at Univ. Cagliari, V. Blum at FHI Berlin, to start with).
    I have also worked on the implementation of hybrid DFT-Hartree-Fock features in Quantum ESPRESSO. Although considerably more computationally demanding than LDA/GGA formulations, hybrid functionals (B3LYP, PBE0,…) appear to be more predictive in a number of thermochemistry calculations. Moreover, any further attempt to model more accurately the correlation part of the XC functional could be spoiled by a poor treatment of exchange.

Publications

SdG is author of more than 100 scientific papers published in international journals and refereed conference proceedings (112 on ISI: 2 renowned, >500 quotes; 1 famous, 250-499 quotes; 5 very well know, 100-249 quotes). These papers have been cited more than 4900 times in the international literature (H32, source: ISI, January 2011).

SdG’s recent publications :

  1. K. Umemoto, R.M. Wentzcovitch, S. Baroni, and S. de Gironcoli, First-principles investigation of order-disorder phase boundary in ice, Geochim. Cosmochim. Acta 74, A1065 (2010).
  2. K. Umemoto, R.M. Wentzcovitch, S. de Gironcoli, and S. Baroni, Order-disorder phase boundary between ice VII and VIII obtained by first principles Chem. Phys. Letters 499, 236-240 (2010).
  3. P. Ghosh, R. Pushpa, S. de Gironcoli, and S. Narasimhan, Effective coordination number: A simple indicator of activation energies for NO dissociation on Rh(100) surfaces, Phys. Rev. B 80, 233406 (2009).
  4. P. Giannozzi, S. Baroni, N. Bonini, M. Calandra, R. Car, C. Cavazzoni, D. Ceresoli, G.L. Chiarotti, M. Cococcioni, I. Dabo, A. Dal Corso, S. de Gironcoli, S. Fabris, G. Fratesi, R. Gebauer, U. Gerstmann, C. Gougoussis, A. Kokalj, M. Lazzeri, L. Martin-Samos, N. Marzari, F. Mauri, R. Mazzarello, S. Paolini, A. Pasquarello, L. Paulatto, C. Sbraccia, S. Scandolo, G. Sclauzero, A.P. Seitsonen, A. Smogunov, P. Umari, and R.M. Wentzcovitch, Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials, J. Phys.: Cond. Matt. 21, 395502 (2009).
  5. Z. Wu, J.F. Justo, C.R.S. da Silva, S. de Gironcoli, and R.M. Wentzcovitch, Anomalous thermodynamic properties in ferropericlase throughout its spin crossover transition, Phys. Rev. B 80, 014409 (2009).
  6. L. Bianchettin, A. Baraldi, S. de Gironcoli, E. Vesselli, S. Lizzit, G. Comelli, and R. Rosei, Surface Core Level Shift: High Sensitive Probe to Oxygen-Induced Reconstruction of Rh(100), J. Phys. Chem. C 113, 13192-13198 (2009).
  7. H.V. Nguyen, and S. de Gironcoli, Efficient calculation of exact exchange and RPA correlation energies in the adiabatic-connection fluctuation-dissipation theory, Phys. Rev. B 79, 205114 (2009).
  8. R. Pushpa, P. Ghosh, S. Narasimhan, and S. de Gironcoli, Effective coordination as a predictor of adsorption energies: A model study of NO on Rh(100) and Rh/MgO(100) surfaces, Phys. Rev. B 79, 165406 (2009).
  9. H.V. Nguyen, and S. de Gironcoli, Van der Waals coefficients of atoms and molecules from a simple approximation for the polarizability, Phys. Rev. B 79, 115105 (2009).
  10. P. Gava, A. Kokalj, S. de Gironcoli, and S. Baroni, Adsorption of chlorine on Ag(111): No subsurface Cl at low coverage, Phys. Rev. B 78, 165419 (2008).
  11. G. Murdachaew, S. de Gironcoli, and G. Scoles, Toward an accurate and efficient theory of physisorption. I. Development of an augmented density-functional theory model, J. Phys. Chem. A 112, 9993-10005 (2008).
  12. M.J. Gillan, D. Alfe, S. de Gironcoli, and F.R. Manby, High-precision calculation of Hartree-Fock energy of crystals, J. Comp. Chem. 29, 2098-2106 (2008).
  13. P. Ghosh, R. Pushpa, S. de Gironcoli, and S. Narasimhan, Interplay between bonding and magnetism in the binding of NO to Rh clusters, J. Chem. Phys. 128, 194708 (2008).
  14. E. Vesselli, L. Bianchettin, A. Baraldi, A. Sala, G. Comelli, S. Lizzit, L. Petaccia, and S. de Gironcoli,The Ni3Al(111) surface structure: experiment and theory, J. Phys.-Cond. Matter 20, 195223 (2008).
  15. A. Kokalj, P. Gava, S. de Gironcoli, and S. Baroni, What determines the catalyst’s selectivity in the ethylene epoxidation reaction, J. Catal. 254, 304-309 (2008).
  16. L. Bianchettin, A. Baraldi, S. de Gironcoli, E. Vesselli, S. Lizzit, L. Petaccia, C. Comelli, and R. Rosei, Core level shifts of undercoordinated Pt atoms, J. Chem. Phys. 128, 114706 (2008).
  17. M. Alaei, H. Akbarzadeh, H. Gholizadeh, and S. de Gironcoli, CO/Pt(111): GGA density functional study of site preference for adsorption, Phys. Rev. B 77, 085414 (2008).
  18. A. Kokalj, P. Gava, S. de Gironcoli, and S. Baroni, Activated adsorption of ethylene on atomic-oxygen-covered Ag(100) and Ag(210): Formation of an oxametallacycle, J. Phys. Chem. C 112, 1019-1027 (2008).