NONPERTURBATIVE BEHAVIOR OF A HYDROGEN-ATOM IN A VAN-DER-WAALS FIELD

The spectrum of the hydrogen atom perturbed by the generalized van der Waals interaction Delta V(x,y,z)=gamma(x(2)+y(2)+beta(2)z(2)) is analyzed with a nonperturbative method of global approximation on a subspace grid. Considerable deviation from the perturbation formulas and violation of the analytic spectrum, which the system exhibits in special cases of the dynamical symmetry beta=1/2, 1, and 2, have already been found for the field strengths H=root 8 gamma similar to 10(-3) a.u. similar to 10(6) G, in the region gamma n(4) much less than 1 (n similar to 10).