INVESTIGADORES
SCHERLIS PEREL Damian Ariel
artículos
Título:
A Quantum-Mechanics Molecular-Mechanics scheme for extended systems
Autor/es:
DIEGO HUNT; VERONICA M SANCHEZ; DAMIAN A. SCHERLIS
Revista:
JOURNAL OF PHYSICS CONDENSED MATTER
Editorial:
IOP PUBLISHING LTD
Referencias:
Lugar: Londres; Año: 2016
ISSN:
0953-8984
Resumen:
We introduce and discuss a hybrid quantum-mechanics molecular-mechanics (QM-MM) approach forCar-Parrinello DFT simulations with pseudopotentials and planewaves basis, designed for the treatmentof periodic systems. In this implementation the MM atoms are considered as additional QM ions havingfractional charges of either sign, which provides conceptual and computational simplicity by exploiting themachinery already existing in planewave codes to deal with electrostatics in periodic boundary conditions.With this strategy, both the QM and MM regions are contained in the same supercell, which determines theperiodicity for the whole system. Thus, while this method is not meant to compete with non-periodic QMMMschemes able to handle extremely large but finite MM regions, it is shown that for periodic systems of afew hundred atoms, our approach provides substantial savings in computational times by treating classicallya fraction of the particles. The performance and accuracy of the method is assessed through the study ofenergetic, structural, and dynamical aspects of the water dimer and of the aqueous bulk phase. Finally,the QM-MM scheme is applied to the computation of the vibrational spectra of water layers adsorbedat the TiO2 anatase (101) solid-liquid interface. This investigation suggests that the inclusion of a secondmonolayer of H2O molecules is sufficient to induce on the first adsorbed layer, a vibrational dynamics similarto that taking place in the presence of an aqueous environment. The present QM-MM scheme appears asa very interesting tool to efficiently perform molecular dynamics simulations of complex condensed mattersystems, from solutions to nanoconfined fluids to different kind of interfaces.