2025-04-30 FF fitting meeting

ThermoML data issues

• Filtering out the mis-entered bromine data and re-fitting makes the bromine properties worse

• Lead team decided not to release this force field

• JC – Why is “incorrect pressure” in the “removed” category and not the “fixed”?

  • LW – Because we only want to fit to atmospheric pressure data, and the “incorrect pressure” point was at very high pressure in expt.

• MT (slide 11) – Above 1.3ish in density are all alkyl bromides?

  • LW – Yes, above that are alkyl bromides, usually increasing in proportion to their mole fraction for mixtures

• CC – slide 10 – details?

  • LW – Sage 2.0 was trying to minimize the error, but didn’t do so in a way that hurt the overall stats

• JC – slide 11 – bottom right figure – seem to be some groups/arcs of outliers. Are those worth looking into?

  • LW – I think we looked into those and concluded there wasn’t an issue.

  • BM – Yeah, we looked at mole fractions, but I haven’t looked at pressures/missing smiles.

  • LW – I checked pressure… shared some tools to extract this data for analysis.

  • BM – Could contact Damien at NIST with this info.

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