INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A new semiempirical potential to represent molecule-metal interfaces. Applications to thiol-capped Au nanoparticles
Autor/es:
JIMENA A. OLMOS ASAR; ARNALDO RAPALLO; MARCELO M. MARISCAL
Lugar:
Cancún
Reunión:
Congreso; XIX International Materials Research Congress; 2010
Resumen:
p.sdendnote { margin-left: 0.2in; text-indent: -0.2in; margin-bottom: 0in; font-size: 10pt; }p { margin-bottom: 0.08in; }a.sdendnoteanc { font-size: 57%; } Nowadays, nanomaterials are of great interest in several research areas as well on many technological applications, mainly due that they have some properties that depend specifically on their size and geometry. Those materials are useful when a high area/volume ratio is required. Some of their applications include biosensors, catalysis, drug “delivery” and construction of nano-circuitsi,ii,iii. Preparation, conservation and protection of metallic nanoparticles require passivation with organic ligand molecules if they will remains in a colloidal suspension. When nanoparticles are made of gold, a relatively easy way of protect them is through organic molecular self-assembly, particularly with thiols molecules due to the strong interaction between sulfur and gold atoms. Self-assembly monolayer’s (SAM’s) have been intensively studied, at experimentaliv,v,vi and theoretical levelvii,viii,ix,x, on extended gold (111) surfaces. Nevertheless, a clear understanding about some fundamental structural aspects of passivated Au nanoparticles in the range of 1-10 nm still does not exist. In the present talk we show a new semiempirical approach to describe molecule-metal interfaces in a realistic way. Using Density Functional calculations ( DFT) in combination with the bond-order concept we have developed a new semiempirical framework which in principle is very simple and easy to implement in standard molecular dynamics codes. In particular we show a parameterization for S – Au. The new potential is used in combination with classical force-fields and the second-moment approximation of the tight binding (SMTB) to reproduce the adsorption of alkanethiol molecules on Au planar surfaces and nanoparticles by means of molecular dynamics simulations. i A. Manna, T. Imae, K. Aoi, M. Okazaki, Mol. Simul. 29 (2003) 661 ii R. Hong, G. Han, J. M. Fernández, B. J. Kim, N. S. Forbes, V. M. Rotello, J. Am. Chem. Soc. 128 (2006) 1078 iii M. M. Mariscal and S. A. Dassie, Recent Advances in Nanoscience, Research Signpost Pub. - Trivandrum, India (2007). iv A. Ulman, S. D. Evans, Y. Shnidman, R. Sharma, E. Eilers, J. C. Chang, J. Am. Chem. Soc. 113 (1991) 1499 v D. J. Lavrich, S. M. Wetterer, S. L. Bernasek, G. Scoles, J. Phys. Chem. B 102 (1998) 3456 vi C Vericat, G A Benitez, D E Grumelli, M E Vela and R C Salvarezza, J. Phys.: Condens. Matter 20 (2008) 184004 vii J. Hautman, M. Klein, J. Chem. Phys. 91 (1989) 4994 viii A. Pertsin, M. Grunze. Langmuir 10 (1994) 3668 ix Y. Yourdshahyan, A. M. Rappe, J. Chem. Phys. 117 (2002) 825 x M. J. Esplandiú, M. L. Carot, F. P. Cometto, V. A. Macagno, E. M. Patrito, Sur. Sci. 600 (2006) 155