Anisotropic Zeeman Effect in Erbium Ethylsulfate When the Magnetic Field is Perpendicular to theCUniaxis of the Crystal

摘要

When single crystals of erbium ethylsulfate, possessingC26hsymmetry, were placed in a magnetic field with the direction of the field, the direction of the incident light, and the crystallinecaxis mutually perpendicular, the energy and intensity of certain of the absorption lines were found to exhibit a dependence on the angle phgr;mbetween the direction of the magnetic field and a newlyhyphen;defined crystallinexaxis. Both the energy and intensity were periodic under 60deg; rotation about thecaxis, but the maximum or minimum energy of every line occurred at phgr;m=0deg;+n60deg;, while the maximum or minimum intensities of all the lines did not occur at a common angle. The energies of the levels, and their rotation coefficients and Zeeman splittings were determined for the ground term and for the line group at 27 500 cmminus;1. The spectral data were used in the measurement of the angle phgr;macr; between the usual crystallographicaaxis and thexaxis. This angle is a new observable which is a consequence of theC3hpoint symmetry at the rarehyphen;earth ion site and which is characteristic of the crystalline environment. The experimental findings are in qualitative agreement with the theoretical work of Murao, Spedding, and Good, and with the results of our extended calculations.