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Re: water molecule



Regarding Thomas O'Neill's answer:
...
Long Answer:
involves so many adjustable parameters that the exercise seems pointless to
anyone but a chemist. ...

to Justin Parke's question:

Does anyone know how much charge is associated with the oxygen atom and the
hydrogen atoms in a water molecule? ...

The answer not only depends on "many adjustable parameters", but it
is not even objectively well defined until one comes up with an
objective scheme to define the precise domain of each atom in the
molecule so that some measure of the charge therein could be measured
or calculated. What *is* well defined is the electric dipole moment
of the water molecule. This dipole moment is due to a smeared
electron charge distribution about the nuclei. But just how much of
the charge distribution is supposed to be "associated with" a given
atom is dependent on just how one divides up the space around the
nuclei among the atoms involved.

I suppose that one scheme that could be implemented is to imagine
that all the charge is concentrated on the locations of the mean
centers of the nuclei, and then assign whatever charge to each
nucleus is necessary to give the correct dipole moment for the
whole molecule. Is this what Justin want's to know?

David Bowman
David_Bowman@georgetowncollege.edu