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Methane: Isotropic model
Summary:
- ISA charge model for electrostatics. No damping.
- L1, isotropic undamped polarization model.
$C_{6}$, isotropic damped dispersion model.
- Isotropic exchange-repulsion terms only.
Units: Atomic Units
Citations
A. J. Misquitta & A. J. Stone, //Ab initio atom–atom potentials using CamCASP: Theory//
Geometry and charges
Source: BS-ISA, A+DF $\zeta=0.1$ aug-cc-pVTZ main basis with aQZ/set2 aux basis. PBE0/AC. CamCASP 5.8.
<code | CH4-ISA.mom>
! Based on DF-type : ISA
C 0.00000000 0.00000000 0.00000000 Type C Rank 0
-0.413530
H1 0.00000000 2.07703578 0.00000000 Type H Rank 0
0.103598
H2 1.69589261 -0.69234525 0.97912406 Type H Rank 0
0.103383
H3 -1.69589261 -0.69234525 0.97912406 Type H Rank 0
0.103383
H4 0.00000000 -0.69234525 -1.95824810 Type H Rank 0
0.103166
Polarizability
Source: Averaged terms taken from WSM L3,aniso. Main basis: d-aug-cc-pVTZ; Aux-basis: aug-cc-pVQZ. PBE0/AC with ALDA+CHF kernel. CamCASP 5.8.
<code | CH4-averaged.pol> # Static polarizabilities C C 0.000 0.0000000 0.0000000 0.0000000 0.000 5.8092410 0.0000000 0.0000000 0.000 0.0000000 5.8092410 0.0000000 0.000 0.0000000 0.0000000 5.8092410 H1 H1 0.000 0.0000000 0.0000000 0.0000000 0.000 2.9408067 0.0000000 0.0000000 0.000 0.0000000 2.9408067 0.0000000 0.000 0.0000000 0.0000000 2.9408067 H2 H2 0.000 0.0000000 0.0000000 0.0000000 0.000 2.9408067 0.0000000 0.0000000 0.000 0.0000000 2.9408067 0.0000000 0.000 0.0000000 0.0000000 2.9408067 H3 H3 0.000 0.0000000 0.0000000 0.0000000 0.000 2.9408067 0.0000000 0.0000000 0.000 0.0000000 2.9408067 0.0000000 0.000 0.0000000 0.0000000 2.9408067 H4 H4 0.000 0.0000000 0.0000000 0.0000000 0.000 2.9408067 0.0000000 0.0000000 0.000 0.0000000 2.9408067 0.0000000 0.000 0.0000000 0.0000000 2.9408067
Potential & Damping
Coefficients fitted using Orient. Tang-Toennies damping. Single dispersion damping coefficient, no induction damping.
<code| CH4-iso-noscale.pot>
C C rho alpha
00 00 0 6.385765 1.821834
END
C H rho alpha
00 00 0 4.843003 1.709089
END
H H rho alpha
00 00 0 4.264730 1.610623
END
! Damping
Induction DAMPING OFF
Dispersion damping Factor 1.93
! Dispersion
C C C6
00 00 0 22.07923
END
C H C6
00 00 0 10.09522
END
H H C6
00 00 0 4.87260
END
Sample Orient command file
You will need the above files present in the directory as they are included into this Orient file.
Orient version: 4.7/4.8
<code | CH4_2-iso-noscale.ornt>
UNITS BOHR
Parameters
Sites 100 polarizable 100
S-functions 50000
Alphas 50000
Parameter-sets 50000
Pairs 100000
Molecules 10
End
Types
C Z 6
H Z 1
End
Variables
Rx 10.0 B
Ry 0.0 B
Rz 0.0 B
alpha 0.0 D
Nx 0.0
Ny 0.0
Nz 1.0
Index 0
End
Molecule CH4_A at 0 0 0 rotated by 0 about 0 0 1
#include CH4-ISA.mom
End
Polarizabilities for CH4_A
Read rank 1
#include CH4-averaged.pol
End
Limit rank 1 for C H1 H2 H3 H4
End
Molecule CH4_B at Rx Ry Rz rotated by alpha about Nx Ny Nz
#include CH4-ISA.mom
End
Polarizabilities for CH4_B
Read rank 1
#include CH4-averaged.pol
End
Limit rank 1 for C H1 H2 H3 H4
End
Pairs
#include ./CH4-iso-noscale.pot
End
Units Bohr kJ/mol
Switch Induce On Iterate On
Options
Induction Iterations 100 Convergence 1e-12
End
Units Bohr kJ/mol
Comment "Energy calculation"
Energy Table Format e15.7 Print es er ind disp total
Variables
Index Rx Ry Rz alpha Nx Ny Nz
2 0.00 -4.20 0.00 180 1.000 0.000 0.000
3 0.00 -4.90 0.00 180 1.000 0.000 0.000
4 0.00 -5.60 0.00 180 1.000 0.000 0.000
5 0.00 -6.30 0.00 180 1.000 0.000 0.000
6 0.00 -6.65 0.00 180 1.000 0.000 0.000
7 0.00 -7.00 0.00 180 1.000 0.000 0.000
8 0.00 -7.35 0.00 180 1.000 0.000 0.000
9 0.00 -7.70 0.00 180 1.000 0.000 0.000
10 0.00 -8.40 0.00 180 1.000 0.000 0.000
11 0.00 -9.10 0.00 180 1.000 0.000 0.000
12 0.00 -9.80 0.00 180 1.000 0.000 0.000
End
FinishOutput should end with
<code | end of output>
Rx Ry Rz alpha Nx Ny Nz Index es er ind disp total
2.00000 0.00000 -4.20000 0.00000 180.00000 1.00000 0.00000 0.00000 1.852709 270.656528 -0.419132 -60.450602 211.639503
3.00000 0.00000 -4.90000 0.00000 180.00000 1.00000 0.00000 0.00000 0.856593 86.890807 -0.131608 -30.904873 56.710918
4.00000 0.00000 -5.60000 0.00000 180.00000 1.00000 0.00000 0.00000 0.419628 27.785414 -0.045079 -15.948023 12.211940
5.00000 0.00000 -6.30000 0.00000 180.00000 1.00000 0.00000 0.00000 0.216730 8.862980 -0.016705 -8.440580 0.622426
6.00000 0.00000 -6.65000 0.00000 180.00000 1.00000 0.00000 0.00000 0.158628 5.002940 -0.010451 -6.218482 -1.067364
7.00000 0.00000 -7.00000 0.00000 180.00000 1.00000 0.00000 0.00000 0.117429 2.823483 -0.006652 -4.624501 -1.690240
8.00000 0.00000 -7.35000 0.00000 180.00000 1.00000 0.00000 0.00000 0.087870 1.593318 -0.004303 -3.472697 -1.795812
9.00000 0.00000 -7.70000 0.00000 180.00000 1.00000 0.00000 0.00000 0.066424 0.899110 -0.002827 -2.633554 -1.670847
10.00000 0.00000 -8.40000 0.00000 180.00000 1.00000 0.00000 0.00000 0.039048 0.286367 -0.001274 -1.559318 -1.235177
11.00000 0.00000 -9.10000 0.00000 180.00000 1.00000 0.00000 0.00000 0.023758 0.091261 -0.000605 -0.958023 -0.843608
12.00000 0.00000 -9.80000 0.00000 180.00000 1.00000 0.00000 0.00000 0.014907 0.029108 -0.000302 -0.608855 -0.565141