SCM: Examples

MM Dispersion

Sample directory: adf/MM_Dispersion/

Example shows a geometry optimization of a van der Waals complex of two benzene molecules, connected to each other with a hydrogen molecule. With the MMDISPERSION keyword an extra empirical force (of similar form as in molecular mechanics) is added to the interaction between the three fragments, where one benzen molecule is fragment 1 (FD=1), the other benzene molecule is fragment 2 (FD=2), and the hydrogen molecule is fragment 3 (FD=3).

The atomic parameters are read from the file $ADFRESOURCES/MMDispersion/disp-param. The PBE functional and the TZP basis set are used, which is necessary if one wants to use the TZ parameters for the damping function, which are optimized for this combination of functional and basis set.

$ADFBIN/adf << eor
basis
  type TZP
  core small
End
XC
  GGA PBE 
End
geometry
  converge grad=0.001
  iterations 5
end
Integration  4.5
SCF
  Iterations  60
  Converge  1.0E-06  1.0E-6
End
mmdispersion
  damping sigm
  damp_param tz
  combi s-k
  file_name $ADFRESOURCES/MMDispersion/disp-param
  nodefault
end
noprint sfo
Atoms   cartesians
C.ctr  0.000000000000     3.050000000000     1.391500000000  FD=1
H.h    0.000000000000     3.050000000000     2.471500000000  FD=1
C.ctr  1.205074349366     3.050000000000     0.695750000000  FD=1
H.h    2.140381785453     3.050000000000     1.235750000000  FD=1
C.ctr  1.205074349366     3.050000000000    -0.695750000000  FD=1
H.h    2.140381785453     3.050000000000    -1.235750000000  FD=1
C.ctr -0.000000000000     3.050000000000    -1.391500000000  FD=1
H.h   -0.000000000000     3.050000000000    -2.471500000000  FD=1
C.ctr -1.205074349366     3.050000000000    -0.695750000000  FD=1
H.h   -2.140381785453     3.050000000000    -1.235750000000  FD=1
C.ctr -1.205074349366     3.050000000000     0.695750000000  FD=1
H.h   -2.140381785453     3.050000000000     1.235750000000  FD=1
C.ctr -1.205074349366    -3.050000000000    -0.695750000000  FD=2
H.h   -2.140381785453    -3.050000000000    -1.235750000000  FD=2
C.ctr -0.000000000000    -3.050000000000    -1.391500000000  FD=2
H.h   -0.000000000000    -3.050000000000    -2.471500000000  FD=2
C.ctr  1.205074349366    -3.050000000000    -0.695750000000  FD=2
H.h    2.140381785453    -3.050000000000    -1.235750000000  FD=2
C.ctr  1.205074349366    -3.050000000000     0.695750000000  FD=2
H.h    2.140381785453    -3.050000000000     1.235750000000  FD=2
C.ctr -0.000000000000    -3.050000000000     1.391500000000  FD=2
H.h   -0.000000000000    -3.050000000000     2.471500000000  FD=2
C.ctr -1.205074349366    -3.050000000000     0.695750000000  FD=2
H.h   -2.140381785453    -3.050000000000     1.235750000000  FD=2
H.h    0.0                0.35               0.0             FD=3
H.h    0.0               -0.35               0.0             FD=3
End
End Input

Search: