  Atomic effective one-electron potentials in a compact analytic form in terms
of a few Gaussian charge distributions are developed, for Hydrogen through
Nobelium, for starting molecular electronic structure calculations by a simple
diagonalization. For each element, all terms but one are optimized in an
isolated-atom Hartree--Fock calculation, and the last one is parametrized on a
set of molecules. This one-parameter-per-atom model gives a good starting guess
for typical molecules and may be of interest even on its own.
