Recently, I have been reading up on articles relating to the dipole moments of different molecules (specifically this). I see how they can get bond lengths and experimental dipole moments with reasonable accuracy and compare that to the theoretically predicted values.

What I don't get is the how theoretical prediction of dipole moment happens. I know that dipole moment equals the charge times the separation distance (u=q*d). So I must be able to predict the dipole (making sure its a vector) of any molecule given its distance of separation and partial charge on the molecules. The partial charge on the molecule depends on the electronegativity values. But then you can't put the electronegativity values (Pauling or Sanderson or others) directly as charge in the formula. Now, I know that Pauling or any other electronegativity scale is only arbitrarily chosen and is relative to the most electronegative element.

But then, how do we make theoretical estimates of dipole moments? Is there any way of relating the electronegativity values to partial charge on each atom? Or is there an entirely different approach?

I have already read these StackExchange answers - this which answers the 'how' but not by 'how much'

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    $\begingroup$ :/ Plug your molecule in some serious software that gets distances and partial charges right, and lo and behold... $\endgroup$
    – Mithoron
    Aug 9, 2021 at 17:32
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    $\begingroup$ Not possible to make a connection between electronegativity and dipole moments. Forget it. Dipole moments are theoretically calculated by advanced quantum mechanical calculations (which I cannot do), and experimentally determined by microwave spectra (again not a trivial exercise) and by various methods. Still experimental methods give a reliable value. Theoretical calculations are pretty close. $\endgroup$
    – AChem
    Aug 9, 2021 at 17:35
  • $\begingroup$ @Mithoron I have tried this method using ChemAxon's MarvinSketch. I would like to know how reliable are these estimates, and possibly verify it myself. $\endgroup$
    – Prajval K
    Aug 10, 2021 at 4:08
  • $\begingroup$ @M.Farooq Very well, if the method of theoretical calculation of dipole moments is a complex thing, then I would be happy to see a high level overview of the process even if it skips some details without obstructing the understanding of the process. I have not found any resource online explaining the process which I would be more than happy to receive if somebody points that out. $\endgroup$
    – Prajval K
    Aug 10, 2021 at 4:12
  • $\begingroup$ @PrajvalK There is a software called GaussView which allows you to calculate dipole moments for a given structure. You have look up its documentation. Please note not everything is available on the internet and most of the stuff is behind paywalls. $\endgroup$
    – AChem
    Aug 10, 2021 at 4:46