Author Topic: Dipole moment calculation  (Read 87 times)

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Offline lohy

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Dipole moment calculation
« on: August 29, 2022, 13:25 »
Hi,
I am trying to understand how to calculate the dipole moment of a molecule (or a junction).

I have used the two exact script that you put on the manuel for the electron density. https://docs.quantumatk.com/manual/Types/ElectronDensity/ElectronDensity.html   nh3_density.py and nh3_density_multipoles.py

Everything is running, my problem is the results.  I get the result shown below. I am aware that the dipole is a vector and that the length of the vector should be the dipole moment. But both the unit and the size of the dipole moment does not make sense. Could you help me understand how this works?
Why is it Bohr**4*e when the unit is e*bohr? (for the dipole)
And when I convert the length of the vector to Debye (1 Debye = 0.39 e*bohr) the dipole moment is no where near comparable with results from e.g. Gaussain. 

Thanks in advance.

----------------------------------------- output from nh3_density_multipoles.py ---------------------------------------------------
center of mass (bohr)  =  [ 10.56827806   9.91727343   9.60194572] Bohr
monopole   (e)         =  8.00000122768 Bohr**3*e
dipole     (e*bohr)    =  [-9.02093396e-16 -2.84059249e-14 -1.58800480e-14] Bohr**4*e
quadropole (e*bohr**2) =  [[ 1.88237189e+01 -8.12198595e-06 -1.01224738e-05]
 [-8.12198595e-06  1.88237184e+01  7.58701761e-05]
 [-1.01224738e-05  7.58701761e-05  1.61672803e+01]] Bohr**5*e