WEAK-FIELD AND STRONG-FIELD STARK ENERGY-LEVELS OF SYMMETRICAL-TOP DIPOLAR MOLECULES

Perturbation expansions of the energy levels of symmetric top dipolar molecules in weak and strong electric fields (field strength F) are extended up to terms proportional to F3 (for weak fields) and to F-1 (for strong fields). For small quantum numbers, suitable analytical interpolations between the weak- and strong-field expansions are obtained from matrix diagonalization results. For large quantum numbers, where this approach becomes inconvenient, quasiclassical techniques provide these interpolations. The expressions are of use not only in spectroscopy but also in reaction kinetics, e.g., in adiabatic channel treatments of reactions on attractive potentials with cos theta anisotropies.