Dipole moment example
Here is a simple script that will calculate the dipole moment of a molecule1. In this particular case I have used the result for a water molecule from a Wannier function localization calculation. To keep the script simple, I have added the charges of the species as 5th column in the file. You can perhaps change it, so it recognizes O with charge of 6 valence electrons, H with \(1e\), and X - Wannier center with charge of \(-2e\). The coordinates are in Angstroms.
Here is the code
#!/usr/bin/awk -f
# x,y,z in Angstroms
NR > 2 {
mx= mx + $2*$5; my= my + $3*$5; mz= mz + $4*$5;
}
END {
norm=sqrt(mx**2 + my**2 + mz**2);
# Convert to Debye
toD= 4.80320425;
mx= mx*toD; my= my*toD; mz= mz*toD;
norm= norm*toD;
printf("Dipole Moment\t x\t\t y\t\t z\t\t| D.Moment |\n");
printf(" [ Debye ] \t%f\t%f\t%f\t%f\n", mx, my, mz, norm);
}
and here is the .xyz file with the charges added
7
Wannier centres, written by Wannier90 on 6Aug2013 at 14:23:10
X 6.50000026 6.18706578 6.50000000 -2
X 6.50000000 6.71337672 6.50000002 -2
X 6.50000008 6.95339960 6.49999998 -2
X 6.49999971 6.54636884 6.50000000 -2
H 6.50000000 7.09480000 7.26880000 1
H 6.50000000 7.09480000 5.73120000 1
O 6.50000000 6.50000000 6.50000000 6
Here is the output of the program
$ ./dipole_moment.awk waterX.xyz
Dipole Moment x y z | D.Moment |
[ Debye ] -0.000000 1.869302 0.000000 1.869302
This example should be easy to alter, so you can calculate (if you want) the center of the mass of the molecule, the geometrical center, radius of gyration...
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