  We show in this note how many electron irreducible representations of the
Lorentz group L can be expressed in terms of the sums of Slater determinants
and principal minors. In this way the full configuration wave function of
quantum chemistry is derived without any appeal to the Schrodinger equation and
Born-Oppenheimer approximation. In particular the number n of
exchange-correlations between the orbiting electrons and those in the nucleus
may be calculated and therefore the ground state electronic
exchange-correlation energy E readily obtained by dividing the atomic energies
by n. Comparison with measured atomic energies yields values of E very close to
-1 hartrees for the 3 neutral atoms Be, B, and C. This tallies within a few
percent with the best available E estimates. Although calculations were
performed for only 3 atoms the method is perfectly general, however because E
is estimated for metals only, gases are not considered in this paper. The
intimate relationship with density function theory is discussed in the
conclusion.
