Abstract
Large-scale simulations and data analysis are often required to explain neutron scattering experiments to establish a connection between the fundamental physics at the nanoscale and data probed by neutrons. However, to perform simulations at experimental conditions it is critical to use correct force-field (FF) parameters which are unfortunately not available for most complex experimental systems. In this work, we have developed a workflow optimization technique to provide optimized FF parameters by comparing molecular dynamics (MD) to neutron scattering data. We describe the workflow in detail by using an example system consisting of tRNA and hydrophilic nanodiamonds in a deuterated water (D2O) environment. Quasi-elastic neutron scattering (QENS) data show a faster motion of the tRNA in the presence of nanodiamond than without the ND. To compare the QENS and MD results quantitatively, a proper choice of FF parameters is necessary. We use an efficient workflow to optimize the FF parameters between the hydrophilic nanodiamond and water by comparing to the QENS data. Our results show that we can obtain accurate FF parameters by using this technique. The workflow can be generalized to other types of neutron data for FF optimization, such as vibrational spectroscopy and spin echo.
Original language | English |
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Pages (from-to) | 128-137 |
Number of pages | 10 |
Journal | Journal of Computational Physics |
Volume | 340 |
DOIs | |
State | Published - Jul 1 2017 |
Funding
The development workflow was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. The use of Oak Ridge National Laboratory's (ORNL) SNS was sponsored by the Scientific User Facilities Division, Office of BES. We thank Gurpreet K. Dhindsa and Xiang-Qiang Chu from Wayne State University for providing us with the QENS data. The Pegasus workflow was funded by the DOE under contract number DE-SC0012636. This manuscript has been authored by ORNL, which is managed by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. DOE. This product includes software developed by and/or derived from the Globus project (http://www.globus.org/). This research used resources of the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Scientific User Facility supported by the Office of Science of the U.S. DOE under Contract No. DE-AC02-05CH11231. The original NAMD simulations were performed on TITAN at the Oak Ridge Leadership Computing Facility at the ORNL, which is supported by the Office of Science of the U.S. DOE under Contract No. DE-AC05-00OR22725. Part of this research was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility.
Funders | Funder number |
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DOE Office of Scientific User Facility | DE-AC02-05CH11231 |
Office of BES | |
Scientific User Facilities Division | |
U.S. Department of Energy | |
Office of Science | |
Basic Energy Sciences | |
Oak Ridge National Laboratory | |
Wayne State University | DE-AC05-00OR22725, DE-SC0012636 |
Division of Materials Sciences and Engineering |
Keywords
- Biopolymers
- CHARMM
- Force-field optimization
- Molecular dynamics
- Neutron data analysis
- Quasi-elastic neutron scattering