Transients in mercury resonance fluorescence under pulsed electric fields: measurement of differential Stark shifts

Abstract

A Stark effect experiment is presented, which involves the recording of transients in radiation resonantly scattered by a vapour, following the sudden application of an electric field pulse. The theory of this effect is developed from the case where a general step-function perturbation is applied. The transients have the form of damped sinusoidal oscillations: the damping is determined by the rate of radiative decay; the modulation frequencies depend directly on the energy-level splittings caused by the applied field. This technique has been to measure the magnitude and sign of the differential Stark shifts in the 6³P₁ level of ¹⁹⁸Hg and ¹⁹⁹Hg. These lead to a value for the tensor polarizability which is in good agreement with recent measurements. Results are presented of a calculation of the polarizabilities of the 6³P₁ and 6¹S₀ levels based on experimental oscillator strengths.