Analytic First and Second Derivatives for the Fragment Molecular Orbital Method Combined with Molecular Mechanics
• hiroya nakata,
• Dmitri Fedorov
hiroya nakata
Kyocera Kabushiki Kaisha

Corresponding Author:nakata.hiro07@gmail.com

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Dmitri Fedorov
National Institute of Advanced Industrial Science and Technology (AIST)
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## Abstract

Analytic first and second derivatives of the energy are developed for the fragment molecular orbital method interfaced with molecular mechanics in the electrostatic embedding scheme at the level of Hartree-Fock and density functional theory. The importance of the orbital response terms is demonstrated. The role of the electrostatic embedding upon molecular vibrations is analyzed, comparing force field and quantum-mechanical treatments for an ionic liquid and a solvated protein. The method is applied for 100 protein conformations sampled in MD to take into account the complexity of a flexible protein structure in solution, and a good agreement to experimental data is obtained: frequencies from an experimental IR spectrum are reproduced within 17 cm$^{-1}$.
19 May 2020Submitted to International Journal of Quantum Chemistry
19 May 2020Submission Checks Completed
19 May 2020Assigned to Editor
29 May 2020Reviewer(s) Assigned
17 Jun 2020Review(s) Completed, Editorial Evaluation Pending
23 Jun 2020Editorial Decision: Revise Minor