  Molecular dipole moments of analytic density-functional theory are
investigated. The effect of element-dependent exchange potentials on these
moments are examined by comparison with conventional quantum-chemical methods
and experiment for the subset of the extended G2 set of molecules that have
nonzero dipole moment. Fitting the Kohn-Sham [Phys. Rev. 140, A1133 (1965)]
potential itself makes a mean absolute error of less than 0.1 Debye. Variation
of alpha (Slater's [Phys. Rev. 81, 385 (1951)] exchange parameter) values has
far less effect on dipole moments than on energies. It is argued that in
variable alpha methods one should choose the smaller of the two rather than the
geometric mean of the two alpha values for the heteroatomic part of the
linear-combination-atomic-orbital density. Calculations on the dipole moment of
NH2(CH)24NO2 are consistent with earlier calculations and show that varying the
differences between alpha values for atoms with different atomic numbers has
only short-ranged electrostatic effects.
