The branching ratios for radiative decay of H atoms excited in small electric fields (0--5 V/cm) have been calculated for the nl states up to n=6. A simple computational procedure was employed, allowing only for Stark-effect mixing of levels with the same values of the quantum numbers (n,j,
mj). The results are compared with more detailed calculations available for 3l-state decay made using the density-matrix formalism, and new calculations of this type reported here for 4l-state decay. In conjunction with theory, this allowed the domain of validity of the simple computational procedure to be established as a function of n. The results show that the branching ratios depend quite strongly on electric-field magnitude, pointing to the need to exercise caution in measurements of H emissions, and in application of the available data to other problems.
We present an exact, analytic solution for the probability of radiative, cooperative transitions of stationary, weakly coupled atoms in strong light fields. Very simple expressions are obtained for pair-emission and -absorption probabilities by use of the ``dressed-atom'' formalism applied to atoms in solids or nearly at rest in optical traps. Analogies between radiative collisions in gases and the pair transitions encountered in solids, which may be viewed as ``frozen'' radiative collisions, are explored. Conditions are predicted for the occurrence of electric dipole decoupling in the presence of a suitable rotating electric field, similar to the well-known phenomenon of ``magic-angle'' decoupling of magnetic spins due to a rotating magnetic field. Observations of this new effect should permit precision determinations of interaction Hamiltonians in optical pair systems.