Mixed Quantum-Classical Dynamics Using Collective Electronic Variables: A Better Alternative to Electronic Friction Theories

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• 作者：Ilya G. Ryabinkin ; Artur F. Izmaylov
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2017
• 出版时间：January 19, 2017
• 年：2017
• 卷：8
• 期：2
• 页码：440-444
• 全文大小：441K
• ISSN：1948-7185

文摘

An accurate description of nonadiabatic dynamics of molecular species on metallic surfaces poses a serious computational challenge associated with a multitude of closely spaced electronic states. We propose a mixed quantum-classical scheme that addresses this challenge by introducing collective electronic variables. These variables are defined through analytic block-diagonalization applied to the time-dependent Hamiltonian matrix governing the electronic dynamics. We compare our scheme with a simplified Ehrenfest approach and with a full-memory electronic friction model on a 1D “adatom + atomic chain” model. Our simulations demonstrate that collective-mode dynamics with only a few (two to three) electronic variables is robust and can describe a variety of situations: from a chemisorbed atom on an insulator to an atom on a metallic surface. Our molecular model also reveals that the friction approach is prone to unpredictable and catastrophic failures.