FreeDRelax: Computing the Frequency-Dependent NMR Relaxation of ¹H Nuclei in Liquid Water

This repository contains a collection of input files and source code as described in the paper "Computing the Frequency-Dependent NMR Relaxation of ¹H Nuclei in Liquid Water", presenting a computational framework for reliably determining the frequency dependent intermolecular NMR dipole-dipole relaxation rate of spin 1/2 nuclei from MD simulations. The paper was published in the Journal of Chemical Physics is also available on arXiv.

The repository is structured as follows:

• MD: contains the input parameter and topology files for the MD simulations with system sizes of 512, 1024, 2048, 4096 and 8192 molecules. The simulations were performed with the GROMACS 5.0.6 software package. All parameters different from default can be found in SIMXX.mdp while sim1out.mdp include all used parameters. For naming convention, please refer to the Gromacs-5.0.6-manual. The start configurations are stored in START.gro, the corresponding force field parameters can be found in topol.top.

• rwmc: contains the source codes for performing random walker Monte Carlo simulations including examples and Hwang-Freed scaling for correcting the effect of a limited sampling cutoff and periodic boundary conditions.

• sdens: contains the code for computing the intra- and intermolecular relaxation rates including examples.

• R1_R2_comb: contain the codes and examples to calculate the longitudinal (R1) and transverse (R2) relaxation rates.

For questions, please contact the authors