  We analyse a nonadiabatic self-consistent field method by means of an
exactly-solvable model. The method is based on nuclear and electronic orbitals
that are functions of the cartesian coordinates in the laboratory-fixed frame.
The kinetic energy of the center of mass is subtracted from the molecular
Hamiltonian operator in the variational process. The results for the simple
model are remarkably accurate and show that the integration over the redundant
cartesian coordinates leads to couplings among the internal ones.
