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College of Arts and Sciences


Chemistry and Biochemistry Seminar

Friday, April 14, 2017 - 4:00pm

Location: Jones Physical Science Center, Room 006

Speaker: Dr. Sophya Garashchuk, Department of Chemistry and Biochemistry, University of South Carolina

Topic: Molecular Dynamics of Large Systems with Quantum Corrections for Selected Nuclei

Abstract: The classical dynamics of nuclei is adequate in many situations (high temperature, high-energy processes), providing insight into chemical processes. Yet it is well-known that quantum features of nuclear behavior -- the zero-point energy, tunneling and nonadiabatic dynamics – are sometimes important in low-energy reactions and in photochemistry. We are interested in the intermediate regime when quantum-mechanical (QM) behavior of a few selected nuclei influences the properties of a large system. To make qualitative predictions and cheap estimates of the nuclear QM effects we are developing approximate dynamics based on the quantum trajectory (QT) formulation of the Schrödinger equation. The QM effects are incorporated through the quantum potential, computed in the “mean-field” approximation, acting on the trajectory ensemble in addition to the classical potential. Large molecular systems are described in a mixed quantum/ classical QT framework with the QM correction incorporated into selected degrees of freedom [1]. The approximate QT dynamics is combined with the Density Functional Tight Binding to compute the electronic structure on the- fly for systems of up to 200 atoms. Adsorption of quantum hydrogen colliding with the graphene model, C37H15 [2] and isotope effects on properties of P3HT/PCBM blend [3] will be discussed.

 

Sponsored by the College of Arts and Sciences and the Department of Chemistry and Biochemistry 


PDF icon Chemistry and Biochemistry Seminar: April 14, 2017