Fast beam quantum beat study of fine structure evolution in an electric field

Abstract

Stark shifted energy splittings have been calculated in He I (n3D) as a function of static electric field strength. Quantum beats have been observed after beam-foil interaction in 4He I (4 and 53D) for a series of electric fields applied parallel to the helium beam. Frequencies are determined by fitting the theoretical expressions for time evolution of fine structure. Tensor polarisabilities have been deduced.