title: Nonadiabatic Molecular Dynamics for Thousand Atom Systems: A Tight-Binding Approach toward PYXAID.
abstract: Excited state dynamics at the nanoscale requires treatment of systems involving hundreds and thousands of atoms. In the majority of cases, depending on the process under investigation, the electronic structure component of the calculation constitutes the computation bottleneck. We developed an efficient approach for simulating nonadiabatic molecular dynamics (NA-MD) of large systems in the framework of the self-consistent charge density functional tight binding (SCC-DFTB) method. SCC-DFTB is combined with the fewest switches surface hopping (FSSH) and decoherence induced surface hopping (DISH) techniques for NA-MD. The approach is implemented within the Python extension for the ab initio dynamics (PYXAID) simulation package, which is an open source NA-MD program designed to handle nanoscale materials. The accuracy of the developed approach is tested with ab initio DFT and experimental data, by considering intraband electron and hole relaxation, and nonradiative electron-hole recombination in a CdSe quantum dot and the (10,5) semiconducting carbon nanotube. The technique is capable of treating accurately and efficiently excitation dynamics in large, realistic nanoscale materials, employing modest computational resources.
authors.affiliation: Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Sougata
authors.initials: S
authors.lastname: Pal
authors.affiliation: Department of Physics and Astronomy, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Dhara J
authors.initials: DJ
authors.lastname: Trivedi
authors.affiliation: Department of Chemistry, University at Buffalo, The State University of New York , Buffalo, New York 14260-3000, United States.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Akimov
authors.affiliation: Bremen Center for Computational Materials Science, Universität Bremen , Otto-Hahn-Alle 1, 28359 Bremen, Germany.
authors.forename: Bálint
authors.initials: B
authors.lastname: Aradi
authors.affiliation: Bremen Center for Computational Materials Science, Universität Bremen , Otto-Hahn-Alle 1, 28359 Bremen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Frauenheim
authors.affiliation: Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Prezhdo