Analytic first and second derivatives of the energy in the fragment molecular orbital method combined with molecular mechanics. Issue 24 (21st August 2020)

• Record Type: Journal Article
• Authors: Nakata, Hiroya; Fedorov, Dmitri G.
• Is Part Of: International journal of quantum chemistry. Volume 120:Issue 24(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-21
• Subjects: fragment molecular orbital method -- QM/MM -- vibration normal mode analysis; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.26414
• Languages: English
• ISSNs: 0020-7608

Abstract

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 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 molecular dynamics (MD) to take into account the complexity of a flexible protein structure in solution, and a good agreement with experimental data is obtained: Frequencies from an experimental infrared (IR) spectrum are reproduced within 17 cm −1 . Abstract : IR spectra for QM/MM with a large QM region are efficiently computed with the fragment molecular orbital method via an interface of GAMESS to LAMMPS.