Back to Methane Potentials page

Methane: Non-polarisable Isotropic model

Summary:

  1. ISA charge model for electrostatics. No damping.
  2. $C_{6}$, isotropic damped dispersion model.

  3. Isotropic exchange-repulsion terms only.

Units: Atomic Units

Citations

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.

CH4-ISA.mom

<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.

CH4-iso-nonpol.pot

<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

CH4_2-iso-scaled.ornt

<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

Finish

Output should end with

end of output

<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

AJMPublic/potentials/methane/nonpol (last edited 2021-04-07 22:06:20 by bsw388)