Knowledge Bank

For Some time the triplet state of cyclopentanone has been known to exhibit three optically detected magnetic resonance (ODMR) spectra (triads) as opposed to the usual one. One possible explanation given for the origin of the triads is interconversion between electronic configurations,either thermally or quantum mechanically $activated.2$ The most intense triad displays `bizarre’ kinetics at liquid nitrogen temperatures. Phosphorescence, ODMR, PMDR, and MIDP studies of cyclopentanone and some deuterated derivatives in various media have been undertaken in our laboratory. We have found very little shift in ODMR line frequency when cyclopentanone is doped into a hydrocarbon glass matrix. Upon deuteration, the ODMR lines do shift, with the extent of shift depending upon the triad. Time resolved spectra indicate vast differences in the lifetimes of different triads. These findings will be used to build a model which can account for the origin of the triads. $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$Work supported by The National Science Foundation. $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$A. L. Shain and M. Sharnoff, Chem. Phys. Lett. 22, 56 (1973). $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$A. L. Shain and M. Sharnoff, Chem. Phys. Lett. 16, 503 (1972).