Hybrid density functional-molecular mechanics calculations for core-electron binding energies of glycine in water solution

TitleHybrid density functional-molecular mechanics calculations for core-electron binding energies of glycine in water solution
Publication TypeJournal Article
Year of Publication2013
AuthorsNiskanen, J, Arul Murugan, N, Rinkevicius, Z, Vahtras, O, Li, C, Monti, S, Carravetta, V, A gren, H
JournalPhysical Chemistry Chemical Physics
Volume15
Pagination244–254
ISSN14639076 (ISSN)
KeywordsArticle, chemistry, electron, Electrons, Glycine, Hydrogen-Ion Concentration, molecular dynamics, molecular dynamics simulation, pH, Quantum theory, thermodynamics, water
Abstract

We report hybrid density functional theory-molecular mechanics (DFT/MM) calculations performed for glycine in water solution at different pH values. In this paper, we discuss several aspects of the quantum mechanics-molecular mechanics (QM/MM) simulations where the dynamics and spectral binding energy shifts are computed sequentially, and where the latter are evaluated over a set of configurations generated by molecular or Car-Parrinello dynamics simulations. In the used model, core ionization takes place in glycine as a quantum mechanical (QM) system modeled with DFT, and the solution is described with expedient force fields in a large molecular mechanical (MM) volume of water molecules. The contribution to the core electronic binding energy from all interactions within and between the two (DFT and MM) parts is accounted for, except charge transfer and dispersion. While the obtained results were found to be in qualitative agreement with experiment, their precision must be qualified with respect to the problem of counter ions, charge transfer and optimal division of QM and MM parts of the system. Results are compared to those of a recent study [Ottoson et al., J. Am. Chem. Soc., 2011, 133, 3120]. © the Owner Societies 2013.

URLhttp://www.scopus.com/inward/record.url?eid=2-s2.0-84870944796&partnerID=40&md5=927f14dd6fa26154dcedb80dddb39359
DOI10.1039/c2cp43264a