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Methane: Non-polarisable Isotropic model
Summary:
- ISA charge model for electrostatics. No damping.
$C_{6}$, 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
Potential & Damping
Coefficients fitted using Orient. Tang-Toennies damping. Single dispersion damping coefficient.
<code| CH4-iso-nonpol.pot> C C rho alpha 00 00 0 6.386635 1.821348 END C H rho alpha 00 00 0 4.839902 1.707686 END H H rho alpha 00 00 0 4.263985 1.610924 END Dispersion damping Factor 1.93 ! Dispersion C C rho alpha C6 00 00 0 5.552955 2.179220 22.07923 END C H rho alpha C6 00 00 0 4.186650 1.898729 10.09522 END H H rho alpha C6 00 00 0 4.782582 1.647922 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-scaled.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
Molecule CH4_B at Rx Ry Rz rotated by alpha about Nx Ny Nz
#include CH4-ISA.mom
End
Pairs
#include ./CH4-iso-scaled.pot
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 270.249369 0.000000 -60.450602 211.651476
3.00000 0.00000 -4.90000 0.00000 180.00000 1.00000 0.00000 0.00000 0.856593 86.771411 0.000000 -30.904873 56.723131
4.00000 0.00000 -5.60000 0.00000 180.00000 1.00000 0.00000 0.00000 0.419628 27.751366 0.000000 -15.948023 12.222972
5.00000 0.00000 -6.30000 0.00000 180.00000 1.00000 0.00000 0.00000 0.216730 8.853454 0.000000 -8.440580 0.629604
6.00000 0.00000 -6.65000 0.00000 180.00000 1.00000 0.00000 0.00000 0.158628 4.997924 0.000000 -6.218482 -1.061929
7.00000 0.00000 -7.00000 0.00000 180.00000 1.00000 0.00000 0.00000 0.117429 2.820846 0.000000 -4.624501 -1.686225
8.00000 0.00000 -7.35000 0.00000 180.00000 1.00000 0.00000 0.00000 0.087870 1.591933 0.000000 -3.472697 -1.792894
9.00000 0.00000 -7.70000 0.00000 180.00000 1.00000 0.00000 0.00000 0.066424 0.898381 0.000000 -2.633554 -1.668749
10.00000 0.00000 -8.40000 0.00000 180.00000 1.00000 0.00000 0.00000 0.039048 0.286164 0.000000 -1.559318 -1.234106
11.00000 0.00000 -9.10000 0.00000 180.00000 1.00000 0.00000 0.00000 0.023758 0.091203 0.000000 -0.958023 -0.843061
12.00000 0.00000 -9.80000 0.00000 180.00000 1.00000 0.00000 0.00000 0.014907 0.029091 0.000000 -0.608855 -0.564857