ZEEMAN SPECTROSCOPY OF THE LOWEST TRIPLET STATE OF TETRAMETHYL-1, 3-CYCLOBUTANEDITHIONE (TMCBDT)

Abstract

The analysis of high field pulsed Zeeman absorption spectra of the 594.3nm $^{3}A_{u}\leftarrow ^{1}A_{g}$ band of single crystal TMCBDT confirms that only one spin-orbit routs is active. Intensity is thus expected to be polarized solely along the C-S bonds, as $observed.^{1}$ Fitting of the field dependent measurements to a model including variable field and polarization directions with respect to the crystal axes has revealed the presence of a zero-field splitting of $1-3 cm^{-1}$. This cannot be observed directly, however, because only one of the triplet sublevels has an appreciable transition moment amplitude in zero-field. Calculation of predicted Zeeman intensity ration corroborate the above findings.