Materials Simulation Group (Grupo de Simulación de Materiales/GSM). University of Burgos.

In order to understand the physical processes governing the behaviour of matter at the nanometer scale it is mandatory to use computer programs to simulate how these nanoscale systems interact among them. The Materials Simulation Group at the University of Burgos has a broad experience in the use of computer programs to simulate atomic and molecular systems as well as nanostructures (metallic clusters, fullerenes, carbon nanotubes and graphene). We study, among others, geometrical, chemical, electronic and thermal properties of these systems. We make use of commercial programs like Gaussian09 as well as of free codes that we have modified in some cases to suit special needs.

Personnel

• Members: I.G. Ayala, A. Bol, N.A. Cordero, and P.A. Marcos.

Research lines:

Computer simulation of interactions in carbon nanostructures.

We have focused in the last years on the mechanisms behind the surfactant effect some molecules have on carbon nanostructures that allow for easier separation of these nanostructures.We have also studied the structure of graphene oxide nanoribbons as well as the reduction of graphene oxide to get graphene.

Improvement of the current simulation techniques based on the electron density.

Computational methods based on the Density Functional Theory (DFT) rely on approximations to the unknown exact exchange-correlation potential. The Hartree-Fock (HF) method gives very good electron densities in spite of neglecting Coulomb correlation. We have proposed several ways of fine tuning HF calculations to take into account this correlation in a simple way.

Current facilities and infrastructure:

• 3 workstations based on Itanium2 processors with a total of 6 cores and 72 GB of RAM.
• 4 workstations based on Xeon processors with a total of 52 cores and 472 GB of RAM.

Research projects (in the last 5 years):

Independent

• "Computer simulation of the structure and properties of graphene compounds". Funding agency: Castile-Leon regional government. Period: 2008-2010. Amount granted: 10,900 €.
• "Computer simulation of the interactions among carbon nanomaterials, water and surfactants". Funding agency: Ministery for Science and Innovation. Period: 2009-2011. Amount granted: 60,500 €.
• "Computer simulation of the properties of multilayer carbon nanoribbons". Funding agency: Castile-Leon regional government. Period: 2011-2013. Amount granted: 17,500 €.
• Innovación Materiales en Radioprotección y en Industria. Medicina Nuclear. IPM - Ingenieros. S.L. (IP: S.Cuesta-López) Acuerdo de Colaboración y Contrato Articulo 83. 2011-2013. Pre-acuerdo para la renovación del contrato en Septiembre de 2013. Extensión 2013-2014.

In collaboration with other groups in the network

• "Multi-scale modelization and experimental validation of new materials with a nanotechnological basis (MULTINANOMAT)" Funding agency: Ministery for Economy and Competitiveness. Period: 2012-2013. Amount granted: 10,000 €
• "Study of new boron compounds and nanostructures as potential targets for neutron capture cancer therapy" Funding agency: CEI BioTic Granada. Period: 2012. Amount granted: 20,000 €.

In collaboration with other groups outside the network

• "Computer simulation of gas adsorption and of molecular reactions on graphene, porous carbons and nanoparticles", Funding agency: Ministery for Science and Innovation. Period: 2012-2014. Amount granted: 70,000 €

Selection of recent publications (in the last 5 years):

Independent

• "Interaction of sodium bisulfate with mono- and bi-layer graphene" I.G. Ayala and N.A. Cordero; J Nanopart Res.,14,1071 (2012).

In collaboration with other groups in the network

• "Wavepacket revivals in monolayer and bilayer graphene rings" T. García, S. Rodríguez-Bolívar, N.A. Cordero and E. Romera; J. Phys.: Condens. Matter, 25, 235301 (2013).

In collaboration with other groups outside the network

• "Interaction and concerted diffusion of lithium in a (5,5) carbon nanotube" M. Khantha, N.A. Cordero, J.A. Alonso, M. Cawkwell, and L.A. Girifalco; Phys. Rev. B; 78, 115430 (2008).
• "Interaction of Surfactants Containing a Sulfuric Group with a (5,5) Carbon Nanotube" N.A, Cordero and J.A. Alonso; J. Phys. Chem. C, 114, 17249 (2010).
• "Surfactant effect of sulfuric acid on the exfoliation of bilayer graphene." I.G. Ayala, N.A. Cordero and J.A. Alonso; Phys. Rev. B, 84, 165424 (2011).
• "Semiempirical fine-tuning for Hartree–Fock ionization potentials of atomic ions with non-integral atomic number." N.A. Cordero, N.H. March, and J.A. Alonso; Physics Letters A, 377, 2955 (2013).