Relative Oscillator Strengths of CH. The Heat of Dissociation of CH

The absorption spectra of the three electronic band systems of the CH radical have been observed in a graphite furnace containing an atmosphere of H₂ gas. From the measured absorption intensities, the relative f numbers of the 4315 Å to the 3850 Å to the 3143 Å systems are found to be 1:0.62:1.26. By using the known absolute f number of the 4315 Å system and measured total absorptions, CH concentrations and, thus, the heats of formation and dissociation have been calculated. These resulting heats are: ${\mathrm{\Delta H}}_0^{\circ }(\mathrm{CH}\text{)=140.5±2.0\hspace{0.17em}}\mathrm{kcal/mole}$ and $D_0^{\circ }(\mathrm{CH}\text{)=80.7±2.0\hspace{0.17em}}\mathrm{kcal/mole}$ .