Combining the Many-Body GW Formalism with Classical Polarizable Models: Insights on the Electronic Structure of Molecular Solids

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• 作者：Jing Li ; Gabriele D’Avino ; Ivan Duchemin ; David Beljonne ; Xavier Blase
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：July 21, 2016
• 年：2016
• 卷：7
• 期：14
• 页码：2814-2820
• 全文大小：432K
• 年卷期：0
• ISSN：1948-7185

文摘

We present an original hybrid QM/MM scheme merging the many-body Green’s function GW formalism with classical discrete polarizable models and its application to the paradigmatic case of a pentacene crystal. Our calculated transport gap is found to be in excellent agreement with reference periodic bulk GW calculations, together with properly parametrized classical microelectrostatic calculations, and with photoionization measurements at crystal surfaces. More importantly, we prove that the gap is insensitive to the partitioning of pentacene molecules in QM and MM subsystems, as a result of the mutual compensation of quantum and classical polarizabilities, clarifying the relation between polarization energy and delocalization. The proposed hybrid method offers a computationally attractive strategy to compute the full spectrum of charged excitations in complex molecular environments, accounting for both QM and MM contributions to the polarization energy, a crucial requirement in the limit of large QM subsystems.