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Push a quick fix of amide issue in 1.2.1
Problem
Amide bond torsion profile obtained by Parsley 1.2.0 shows significant deviation from QM torsion profile, having flat basin around the QM minimum with a suspicious small peak.
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1. new t70 child parameter candidate
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- Conclusion: Based on the following plots, it seems reasonable to have separate child term [*:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#1] (higher energy barrier) and [*:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#7X3] ( lower energy barrier).
- No clear evidence for the necessity to combine a pattern with carbon attached to the carbonyl carbon ([*:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#6]) and one with hydrogen attached to the carbonyl carbon([*:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#1])
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2. Test fitting
(1) re-fitting #1.1
Separated endo-cyclic and exo-cyclic rotations(
t69aandt69b,t70andt70a): will determine whether to separate or not after comparing the final k values.w/ only selected td targets
w/ old conda env.(openforcefield==0.6.0, forcebalance=1.7.1)
optimized in 6 steps (3.21033e+01 → 7.97182e+00)
SMIRKS | initial guess | fit #1.1 | |
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t69a | [*:1]-[#7X3:2]-[#6X3$(*=[#8,#16,#7]):3]~[*:4] | 2.5 (1+cos(2x-180)) + 0.0 (1+cosx) | 2.130536422094e+00 (1+cos(2x-180)) + 9.910621243621e-02 (1+cosx) |
t69b | [*:1]-[#7X3:2]-!@[#6X3$(*=[#8,#16,#7]):3]~[*:4] | 2.5 (1+cos(2x-180)) + 0.0 (1+cosx) | 2.270075197860e+00 (1+cos(2x-180)) + 3.898905433309e-01 (1+cosx) |
t70 | [#1:1]-[#7X3:2]-[#6X3:3]=[#8,#16,#7:4] | 3.459249459574e+00 (1+cos(2x-180)) + 1.356955617521e+00 (1+cosx) | 3.471614493904e+00 (1+cos(2x-180)) + 1.353665035664e+00 (1+cosx) |
t70a | [#1:1]-[#7X3:2]-!@[#6X3:3]=[#8,#16,#7:4] | 2.5 (1+cos(2x-180)) + 2.0 (1+cosx) | 2.5 (1+cos(2x-180)) + 2.0 (1+cosx) |
t70b | [*:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#6,#1] | 2.5 (1+cos(2x-180)) + 0.0 (1+cosx) | 2.779138641990e+00 (1+cos(2x-180)) + 3.381053683048e-02 (1+cosx) |
t70c | [#1:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#6,#1] | 2.5 (1+cos(2x-180)) + 2.0 (1+cosx) | 2.590468938026e+00 (1+cos(2x-180)) + 1.820091344671e+00 (1+cosx) |
t70d | [*:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#7X3] | 2.5 (1+cos(2x-180)) + 0.0 (1+cosx) | 1.888086753838e+0 (1+cos(2x-180)) - 2.028808021603e-01 (1+cosx) |
QM vs MM torsion profiles
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