Radiative lifetime of high Rydberg states perturbed by a neutral atom

The radiative lifetimes of high Rydberg states perturbed by a neutral atom have been investigated. Calculations have been performed for the 'active' states within the N2 Rydberg manifold with principal quantum numbers N = 20, 25, 30, 35. The energies of these 'active' states are shifted with respect to the unperturbed Coulomb energies. Their lifetimes are found to depend on internuclear distance R between the Rydberg and perturbing atom. In the limit of asymptotically large distances R, the calculated radiative lifetime is equal to that of corresponding Stark state, whereas in the limit R → 0, this parameter is equal to that of the spherical S-state for a given N. However at distances about half of the size of Rydberg electron orbit, the calculated radiative lifetimes are 3-5 times larger than these limit values. (author)