Speaker:Linjun Wang, Professor,Department of Chemistry, Zhejiang University
Date:September 6, 2019
Time: 10:00 am
Location:Hall 1113, Block C, Zhixin Building, Central Campus
Sponsor:the School of Physics
Due to the ease of implementation and good balance between efficiency and reliability, surface hopping has become one of the most widely used mixed quantum-classical methods for studying general charge and exciton dynamics. In extended systems (e.g., molecular aggregates, polymers, surfaces, interfaces, and solids), however, surface hopping suffers from several severe problems, and thus the relevant applications have been limited in the past years. Trivial crossings between uncoupled or weakly coupled states have highly peaked nonadiabatic couplings and thus are difficult to deal with in the preferred, adiabatic representation. Recently, we introduce crossing classification and self-consistent correction to surface hopping. We further show that a proper choice of subspace can significantly simplify the surface crossings. As a result, fast time step convergence and system size independence have been achieved in thousands of molecular sites. In addition, the decoherence and superexchange effects are also important in extended systems. We propose a branching corrected surface hopping, which resets the wavefunction coefficients based on the judgement of wave packet reflection. This approach ensures the self-consistency of using the traditional time-dependent Schrödinger equation to describe mixed quantum-classical dynamics and captures the majority of the real decoherence effect as demonstrated in over two hundred scattering models, surpassing other existed decoherence correction algorithms. We also propose global flux and Liouville space surface hopping, which provide indirect and high-order population transfer channels. With our method developments, complex nonadiabatic dynamics could be simulated with improved efficiency and reliability, thus promising for many applications in chemistry, physics, biology, and material sciences.
Prof. Wang Linjun graduated from the University of Science and Technology of China in 2009. He received his Ph.D. from the Institute of Chemistry of the Chinese Academy of Sciences, and then worked as a postdoctoral researcher at Mons University in Belgium, the University of Rochester in the United States and the University of Southern California. In March 2016, he joined the Department of Chemistry of Zhejiang University. He is a researcher and a doctoral tutor. So far, he has published 59 SCI papers with a total of more than 2,700 citations and an h-factor of 28. His main research field is the non-adiabatic kinetics of the extended system. In recent years,he has developeda series of trajectory surface hopping methodsandsystematically improvedthe efficiency, precision and universality of the hybrid quantum-classical dynamics simulation of complex systemswhich has great application prospects.His other studies include electron/exciton dynamics, semi-classical dynamics, global optimization, and machine learning.
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Edited by:Liu Li