Fluorescence of Fluorobenzene

Abstract

The behavior of the first excited singlet state of monofluorobenzene in the gaseous phase has been examined with aid of spectroscopy and of emission quantum yields. Some resonance emission occurs at short wavelengths of incident radiation at a pressure of 1 torr. This resonance radiation is quenched by foreign gases and a linear plot of ${\text{1\hspace{0.17em}/\hspace{0.17em}Q}}_{\mathrm{rf}}$ vs $p$ is obtained. Absolute emission yields were obtained by use of benzene, for which $Q_f$ at 253 nm is assumed to be 0.18. The total yield of fluorescence is constant over the range $\text{λ\hspace{0.17em}>\hspace{0.17em}258}\mathrm{nm}$ , but below 258 nm the yield decreases. Addition of iso‐C₄H₁₀ enhances the yield at short wavelengths. An apparent diffuseness of the spectrum at short wavelengths may indicate some process such as isomerization or even dissociation.