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Updated: May 20, 2026

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
An improvement in quantum mechanical description of solute-solvent interactions in condensed systems via the
Norio Takenaka1, Yukichi Kitamura, Yoshiyuki Koyano
1Graduate School of Information Science, Nagoya University, Nagoya 464-8601, Japan.
Abstract:
An efficient methodology is presented to improve the QM description of solute-solvent interactions in condensed systems within the quantum mechanical/molecular mechanical (QM/MM) framework. It is based on the recently developed new treatment of the adaptive multiscale QM/MM-MD method, i.e., the number-adaptive multiscale method that includes the close solvent molecules around the solute into QM region and enables them to flow across the boundary between the QM and MM regions. We have applied it to zwitterionic (ZW) glycine molecule in aqueous solution, and investigated the hydration structures and charge distributions, which are compared with those by the standard (SD) method that only a solute glycine molecule is treated quantum mechanically. It is shown that the total energy and temperature are satisfactorily conserved, providing reasonable hydration numbers and induced polarization of ZW glycine molecule in aqueous solution. In contrast, the SD method is found overestimated the hydration numbers in comparison to the experimental ones due to the inappropriate expression of the electron distribution. In conclusion, the present method should become quite useful as the quantitative statistical sampling method to study various chemical phenomena in condensed systems.
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