History

2024.1.10 – Fixed PF6- issue in CL&P forcefield

• The angle parameters for PF6- in the CL&P forcefield only work if the 180º F-P-F angles are not included in the calculation. Replacing them with an equivalent periodic SHAPES-like potential almost works; however, since 0º is a valid angle and there are no 1-3 nonbonds, nothing keeps the F atoms apart. This is solved using a tabulated potential based on the SHAPES potential but with an added 1-3 repulsion large enough that the gradient is always pusing small angles apart, but not large enough to affect the minimum at 90º.

2023.9.14 – Fixed errors! And added C2mim to test.

• The units of the torsions were incorrect in the last implementation.

• Added parameters for 1-alkyl-3-methylimidazolium cations from JCP 108, 2038 (2004)

• Tested much more thoroughly.

2023.9.13 – Added parameters for TFSI to CL&P/OPLSAA

• Parameters for TFSI - bis[(trifluoromethyl)sulfonyl]imide

2023.9.8 – Added more typing for OPLS-AA

• cyclopropane -CH2-, -CHR-, and -CR2-

• hexafluorobenzene

• difluorobenzene

• bromobenzene

• iodobenzene

• thiophenol

• alkyl nitriles

• nitroalkanes

• nitrobenzene

• methylene in phenylacetonitrile

• corrections to methylene nitrile anion

2023.9.7 – Added typing in OPLS_AA for fluorobenzene

2023.9.6 – Fixed issue with PF6- geometry

• The Lennard-Jones repulsive term added to the F-P-F angle was too weak, allowing the structure to get trapped in a symmetric state with ~40º angles.

2023.8.27 – Fixed issue with angle in octahedral systems

• The SHAPES-type simple fourier potential used for octahedral complexes has a fals minimim at 0º. Added a LJ 1/R^12 repulsive term between the two end atoms of the angle to prevent small angles. This required using tabulated potentials in LAMMPS.

2023.5.1 – Fixed bug in Lithium battery forcefield

• Fixed a typo in the angle type unit line which caused a crash

2023.4.6 – Added Lithium battery forcefield

• An initial set of parameters for cathode materials, specifically LiCoO2.

2023.2.13 – Added OPLS-AA forcefield

• Added parameters for OPLS-AA along with some extra parameters for ionic liquids * PF6- * ethylene carbonate (EC) and fluoronated EC (FEC)

• Added atom-typing templates for most of OPLS-AA. Still missing a few and amino acids and DNA not yet tested.

• Added extensive, almost-complete testing, for OPLS-AA

2021.2.10 (10 February 2021)

• Updated the README file to give a better description.

• Updated the short description in setup.py to work with the new installer.

• Added keywords for better searchability.

2020.8.1 (1 August 2020)

• Added support for OpenKIM potentials in LAMMPS

0.9.1 (24 May 2020)

• Added the specialized NaCl_water forcefield for testing the MolSSI Driver Interface (MDI) metadynamics driver.

0.9 (15 April 2020)

• Internal changes for compatibility

0.1.0 (24 December 2017)

• First release on PyPI.