Edge Emission and Zeeman Effects in CdS

Some of the sharp, characteristic emission lines, observed in "blue" and "green" edge-fluorescence spectra of CdS platelets, have been examined experimentally at low temperatures (∼1°K). Zeeman effects, in magnetic fields up to 45 000 G, have been studied in doublets of previously reported lines, as well as in several new lines. In particular, the magnetic splitting of $I_5$ (a characteristic "blue" emission line appearing at 4869.14 Å) has been studied as a function of magnetic field orientation (angular orientation of $c$ axis with respect to field direction). In accordance with the Thomas-Hopfield analysis, arguments are presented for the association of $I_5$ with a bound exciton complex; this line was observed to split linearly as a function of field strength and a $g$ value of -1.76 ($c\perp H$) is reported. Several zero-field split lines (fluorescent doublets) have been studied as a function of field orientation: $I_1$ (4888.47, 4888.18 Å), $I_2$ (4867.17, 4866.98 Å), and $I_3$ (4861.66, 4862.25 Å). The lines $I_1$ (doublet) and $I_2$ (doublet) were observed to split linearly as a function of field strength and a $g$ value of -1.77 ($c\perp H$) is reported for $I_1$. In particular crystals, pronounced thermalization effects have been observed in the fluorescent singlets $I_1$ (4888.47 Å), $I_2$ (4867.17 Å) and $I_5$, i.e., line thermalization was observed as a function of magnetic splitting at constant temperature. Two sharp, long-wavelength lines have also been observed, namely $I_6$ (5068.54, 5069.18 Å) and $I_7$ (5084.81 Å). The polarization and magnetic splittings of $I_6$ and $I_7$ are reported.