On the Dissociation Energy of Carbon Monoxide and the Heat of Sublimation of Carbon

None of the values of the dissociation energy of carbon monoxide, $D\left(\mathrm{CO}\right)$, proposed on the basis of interpretations of predissociations in the spectrum of CO is in satisfactory agreement with the results of electron-impact experiments. The only possible interpretation of these experiments gives $D\left(\mathrm{CO}\right)=9.6\mathrm{}$ ev. Compelling reasons can be given for considering this result of sufficient accuracy to make it irreconcilable with any of the values from the band spectrum. A new interpretation of the effects in the spectrum which brings agreement with the electron impact value is possible, however. It involves a potential curve with maximum for $J=0\mathrm{}$ for the state $a^{\prime }{}_{}{}^3{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ of CO which predissociates $B{}_{}{}^1{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ and $b{}_{}{}^3{}_{}{}^{}\Sigma _{}^{+}{}_{}{}^{}$ at 11.11 ev. Various data favor this interpretation and its consequences. Satisfactory agreement among all data bearing on $D\left(\mathrm{CO}\right)$ and $L_1\left(\mathrm{C}\right)$, the heat of sublimation of carbon, can be attained in this way.