BECAS
SANCHEZ Juan Pablo
congresos y reuniones científicas
Título:
High level calculations on C54H18 / H2: A simple model of the adsorption of hydrogen on graphene
Autor/es:
J.G. LUGO; J.P. SANCHEZ; I.G. CUESTA; J. SÁNCHEZ-MARÍN; A.M.J. SÁNCHEZ DE MERÁS
Lugar:
Santiago de Compostela
Reunión:
Congreso; Ninth Triennial Congress of the WORLD ASSOCIATION OF THEORETICAL AND COMPUTATIONAL CHEMISTS-WATOC 2011; 2011
Resumen:
Even though some controversy exists, especially with respect to thereproducibility of the experimental observations, carbon structures have been proposed as promising candidates to store hydrogen, an ideal material for energy production. In particular, graphene can be, once properly doped, a suitable material to design such devices since its synthesis is simpler than that of, for instance, carbon nanotubes.Theoretical methods can contribute to clarify the discrepancies found in the experimental work since complications arising from pureness or structural conformation are very easily taken care of. Nevertheless, the special characteristics of the interaction between graphene and hydrogen prevent the use of the DFT approach (at least with cheap standard exchange?correlation potentials). At the same time, the inadequate scaling of theoretical methods with respect to the molecular size makes it very difficult the use of wave function quantum chemical calculations in this context. However, Cholesky decomposition?based techniques can enormously facilitate the calculation of both energy and molecular properties in large size molecular systems because a very compact representation of the two electron integral matrix is obtained by exploiting the characteristic dispersion of large systems with the lineardependencies in the atomic orbital product space. As a first step to model the adsorption of hydrogen on pure and doped graphene sheets, we have studied the interaction between C54H18 and H2 using MP2 calculations with Cholesky decomposed two electron integrals. As this approach tends to overestimate the bonding when mainly due to dispersion contributions, we have tailored the one-electron basis sets in the spirit of Hobza?s 6-31G(d=0.25) basis taking the CCSD(T) interaction of hydrogen and coronene as reference. Furthermore, we explore the possibility of using CCSD(T) calculations in reduced orbital spaces by means of Cholesky localized molecular orbitals.