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orlandoacevedo / IL

Ionic liquid force field parameters (OPLS-2009IL and OPLS-VSIL)
GNU General Public License v3.0
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Sign error of dihedral coeffs of EMIM? #5

Closed gullbrekken closed 3 months ago

gullbrekken commented 3 months ago

In the EMIM_scale0.8.itp file the CW-NA-CA-HA dihedral has coefficients V1 to V4: -2.7 5.65 0.355 0. See line 140 in the file. However, in the original paper "Development of OPLS-AA Force Field Parameters for 68 Unique Ionic Liquids" and in the SI of "Revisiting OPLS Force Field Parameters for Ionic Liquid Simulations", the coefficients for this dihedral are: -2.700 -5.650 0.355. So the second coefficient is negative, while it is positive in the ITP file. I want to simulate a system containing EMIM, so my question is, which value is correct?

gullbrekken commented 3 months ago

I could add that the second coefficient is also positive (5.65) in the EMIM.itp file.

orlandoacevedo commented 3 months ago

Thank you for catching this typo. The value should be negative as reported in the papers (and as listed for BMIM and OMIM). I have updated both EMIM files.

gullbrekken commented 3 months ago

Thank you!