A few revisions, suggested by recent results of Herzberg on ${\mathrm{N}}_2^{+}$, are made in Table III of I, for ${\mathrm{N}}_2^{+}$, CN, and ${\mathrm{O}}_2^{+}$. These revisions involve dissociation of unexcited molecules to give one excited atom or ion. With these revisions, and a revised heat of dissociation for ${\mathrm{N}}_2$, the quantum number assignments previously made are found to be all consistent with Hund's rule of ${\sigma }_l$ and $s$ sums, and, except for one or two states of ${\mathrm{F}}_2$, with the ${\sigma }_{l\tau }$ conservation rule given in I. This result gives needed support to the latter rule. The probable atomic dissociation products are determined for most of the molecular states given in Table III of I. In the cases of ${\mathrm{N}}_2$ and ${\mathrm{N}}_2^{+}$ the probable dissociation products and energies are given in Table I. An interpretation is given of the dissociation processes involved in Hogness and Lunn's NO ionization potentials at 21 and 22 volts, and of their 24 volt ${\mathrm{N}}_2^{+}$ potential. Evidence is brought forward for a revision of Birge and Sponer's values of the heats of dissociation for the normal states of several molecules, in particular ${\mathrm{N}}_2$. Suggested new or revised values are, in volts, ${\mathrm{N}}_2$, 9.5; ${\mathrm{N}}_2^{+}$, 7.1; NO, 7.3; C${\mathrm{O}}^{+}$, 8.3; N${\mathrm{O}}^{+}$, 11.2. The alkali and hydrogen halides are briefly discussed with reference to their electronic states and dissociation products.

• Received 1 July 1928

DOI:https://doi.org/10.1103/PhysRev.32.761