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Psi4 inputs for different grid generation schemes
When using Psi4’s in-built cubic grid
| Code Block |
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set cubeprop_tasks ['esp']
set cubic_grid_spacing [1.1785, 1.1785, 1.1785]
set cubic_grid_overage [8.0, 8.0, 8.0] # size of the cubic grid (default = 4 Bohr)
e, wfn = energy('HF', return_wfn=True)
cubeprop(wfn) |
When using a user-specified grid points specified in
grid.dat
| Code Block |
|---|
E,wfn = prop('HF' , properties = ['GRID_ESP'], return_wfn=True) |
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Generation of FCC grid used for charge fitting
- Generate a box containing the molecule and fill the box with FCC grids
- Select grid points which are inside the outer boundary and outside the inner boundary (shell of points)
( For a comparison, cubic grids were cut to fit in the same shell with FCC grids)
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1. rotational invariance
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Procedure:
(1) Rotated a test molecule(MeOH) by multiples of 0.5 degree about each axis an axis (100 frames)
(2) Generated both cubic grid(using Psi4 in-built feature) and FCC grid, ran ESP generation on each grid, for cubic grid, selected points using the same outer and inner boundary with FCC grids and used for charge fitting.
(3) RESP two stage fit charges were calculated from each frame and calculated standard deviation of charges.
psi4 in-built cubic grids | sc, 2-stg: 0.002658 sc, wk. : 0.002016 | sc, 2-stg: 0.002320 sc, wk. : 0.002438 | sc, 2-stg: 0.002447 sc, wk. : 0.002644 | |||||||||||
FCC grids | fcc, 2-stg: 0.001405 fcc, wk. : | 0.002363fcc, 2-stg: 0.000830 fcc, wk. : 0.001144 | fcc, 2-stg: 0.002252 fcc, wk. : 0.003460 | rotation by 0.5 (100 frames) | rotation by 0.1 (100 frames) | rotation by 0.1 (500 frames) | rotation by 0.05 (100 frames) | psi4 in-built cubic grids | sc, 2-stg: 0.002447 sc, wk. : 0.002644 | sc, 2-stg: 0.001717 sc, wk. : 0.002277 | sc, 2-stg: 0.001902 sc, wk. : | 0.002425 | FCC grids | fcc, 2-stg: 0.002252 fcc, wk. : 0.003460fcc, |
2
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fcc, wk. : 0.001372
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fcc, 2-stg: 0.001153
fcc, wk. : 0.001251
2. translational invariance
psi4 in-built cubic grids | sc, 2-stg: 0.000379 sc, wk. : 0.000074 |
FCC grids | fcc, 2-stg: 0.000644 fcc, wk. : 0.000393 |