Analysis of Paramagnetic Resonance Properties of Pure and Bleached F Centers in Potassium Chloride

Abstract

The electron paramagnetic resonance of color centers in additively colored KCl crystals is measured carefully to observe the effects of optical bleaching at room temperature. Earlier measurements on the F cent~r are confirmed and the s.usceptibility is measured at 78° and 300 0 K over five decades of power, includlllg the very low power regIOn. The width and the saturation properties of the individual multiplets are studied in detail and the technique of making EPR measurements on inhomogeneously broadened lines is discussed. A calculation is presented which shows that a slight departure from a Lorentzian multiplet shape can account for the saturation data.The bleached crystals show a resonance which has a width of 35 gauss and a different rate of saturation than the F center. This resonance is associated with the B band which appears in the optical absorption.

Faraday Rotation for theFBand in KCI

“…At temperatures exceeding about 40°K the magnitude of the total effect is temperature independent and corresponds to the so-called "diamagnetic" or temperature-independent Faraday rotation O^. 1 This effect arises from the Zeeman splitting when equal electron populations exist in the two spin levels of the ground state.…”