NIST Standard Reference Simulation Website

The Standard Reference Simulation Website is an ongoing project whose aim is to provide well-documented simulation results for a variety of systems and from various simulation techniques. The results contained here are usually generated in-house at NIST but, when certain criteria are satisfied, may also include results from provided from outside collaborators.

Molecular simulations, in particular Monte Carlo Molecular Simulation and Molecular Dynamics Simulation, are methods for computing the properties of some kind of system, for which the intermolecular interactions are specified, via mathematical relationships derived from statistical mechanics. Since statistical mechanics itself makes no reference to molecular simulation of any kind, the properties that derive from statistical mechanics should not depend on the particular simulation algorithm used to compute properties for a specified model. Consequently, the results obtained from a molecular simulation can be thought of as characteristic of the model system, subject only to statistical uncertainty in those results, if the simulation technique follows necessary rules (e.g., detailed balance or microscopic reversibility, depending on the particular algorithm) and is computationally robust. Our goal in this project is to publish well-documented simulation results for reliable and well-vetted simulation software for a variety of systems, many of which are commonly used in molecular simulations, that can be treated similar to "standard reference data" that is generated in an laboratory setting. The data contained here may be used to validate and test new or existing molecular simulation software, as reference data, or for other appropriate applications. Most of the results contained here are generated in-house at NIST, but we will also include results from collaborators provided certain criteria are satisfied (see "Criteria..." below). In addition, it is our goal to provide data from molecular simulations in a raw or unprocessed format, when possible, so that the data may be reprocessed according to end users' particular needs. To that end, we also provide some software that may be used to reprocess data contained here.

Systems Available:

• Lennard-Jones
• Stockmayer
• Ethane
• n-Octane
• SPC/E Water
• Hard-Sphere Fluid
  

Criteria for inclusion of simulation reference data

Thermophysical properties of fluids that are entered into this database must conform to the following criteria:

1. Reproducibility: Thermophysical properties reported in this database must also include "metadata" that describes the simulation technique(s) and all simulation parameters used to obtain those properties. Simulation metadata must be sufficiently comprehensive such that an outside researcher could reproduce the properties given here (within the reported statistical uncertainty).
2. Accessible Force Fields: Intermolecular potential models used to generate properties in this database must be available in the scientific literature or fully described in the simulation metadata.
3. Statistical Uncertainty: All properties reported in this database must also include an estimate of the statistical uncertainty in each particular measurement. The statistical uncertainty must be computed using an appropriate technique that is described in the database.
4. Proprietary Software Prohibition: In cases where prepackaged simulation software (e.g., LAMMPS, GROMACS, Towhee, etc.) has been used to generate properties in this database, such simulation software must be open-source and freely available to the scientific community.

Notes:

This site provide thermophysical properties data computed using molecular simulation techniques and compiled by NIST under the Standards Reference Data Program.

The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality database of molecular simulation data and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.

Certain prepackaged simulation programs may be identified in this database. This identification does not imply recommendation or endorsement by NIST, nor does it imply that it is the best available for the purposes described.