Low-field diamagnetism in helium Rydberg states

Abstract
In a CW laser-atomic beam experiment metastable helium atoms are excited to Rydberg states (n=58) in a magnetic field ( approximately=0.1 T). The observed l-mixing spectra are reproduced using the method of diagonalization of the energy matrix as well as semiclassical theories. Also the first anticrossing between n=70 and 71 manifolds is measured accurately and is compared with calculations.