(3) 2020-08-31
toy fitting to n-methylacetamide
When directly fitting to N-methylacetamide, it doesn’t make the hump at 180. So it seems like we have some torsion targets used for the fitting, which force the formation of hump.
qm torsion profiles of the targets
fitting w/o the four targets
qm torsion profiles w/ larger basis set or finer grid (15 degree → 5 degree)
| SMIRKS | fb-fit2 | fb-fit3 |
|---|---|---|---|
t69a | [*:1]-[#7X3:2]-[#6X3$(*=[#8,#16,#7]):3]~[*:4] | 2.5 (1+cos(2x-180)) + 0.0 (1+cosx) | 2.5 (1+cos(2x-180)) |
t69b | [*:1]-[#7X3:2]-!@[#6X3$(*=[#8,#16,#7]):3]~[*:4] | 2.5 (1+cos(2x-180)) + 0.0 (1+cosx) | 2.5 (1+cos(2x-180)) |
t70 | [#1:1]-[#7X3:2]-[#6X3:3]=[#8,#16,#7:4] | 3.459249459574e+00 (1+cos(2x-180)) + 1.356955617521e+00 (1+cosx) | 3.459249459574e+00 (1+cos(2x-180)) + 1.356955617521e+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) | 2.5 (1+cos(2x-180)) |
t70c | [#1:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#6,#1] | 2.5 (1+cos(2x-180)) + 2.0 (1+cosx) | 2.5 (1+cos(2x-180)) + 2.0 (1+cosx) |
t70d | [*:1]-[#7X3:2]-!@[#6X3:3](=[#8,#16,#7:4])-[#7X3] | 2.5 (1+cos(2x-180)) + 0.0 (1+cosx) | 2.5 (1+cos(2x-180)) |