Stark-Induced Temporal Intensity Variations in Spectral Lines

Abstract

The effect of externally produced Stark splitting upon fine-structure-level probabilities is investigated in order to describe periodic intensity variations previously found in hydrogen lines. Coupled differential equations for the probability amplitudes of mixed levels are solved exactly in terms of initial amplitudes; effects due to spontaneous transition probabilities and Lamb shift are included. In general, the time-dependent line intensity is a combination of exponential decays and sinusoidal oscillations. The frequencies of oscillations are discussed in detail, and the effects of different initial conditions upon the intensities are considered for several special cases.