Knowledge Bank

A computer based photon counting technique has enabled temperature dependent fluorescence measurements to be made in an accurate manner on the $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}B2u$ state of crystalline Benzene. The temperature range investigated was $4\circ K$ to $20\circ K$. The fluorescence line shape that was studied was from the (0,0)---$v6$^{\prime\prime} transition. The density of states curve that these experiments yielded agreed in principle with that calcuiated by Colson. However, an improvement in the values chosen for the resonance exchange integrals was obtained. The results of this work leave no doubt that pure exciton emission from a molecular crystal can be seen and that there exists for the case of the $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}B2u$ state of Benzene a theory which can satisfactorily explain the temperature dependence of that emission’s line shape.