"anticrossing" signals in resonance fluorescence

Abstract

The level-crossing technique of atomic spectroscopy utilizes the spatial interference in the scattering of resonance radiation which can occur when two Zeeman levels of an atom are brought into coincidence ("crossed") by the application of an external magnetic field. "Anticrossing" refers to the case where the two levels involved are coupled by a small static interaction. In this paper the general expression for an anticrossing signal is given and its predictions compared with signals observed in the 2 P2 term of Li. It is shown that anticrossings produce signals in many experimental situations for which there would be no signal from a normal level crossing. © 1967 The American Physical Society.