The Emission Spectrum of Diatomic Arsenic. II

The emission spectrum of diatomic arsenic, previously studied in the interval 2100A to 3700A, has been extended to 7000A. The two prominent systems have been greatly extended so that the ground state of the molecule has been followed to $v=70\mathrm{}$, in energy to nearly 0.8 of the heat of dissociation, $D\left(X\right)\mathrm{}$. $D\left(X\right)\mathrm{}$ is 3.9 volts by extrapolation and the same value is obtained from analysis of predissociation occurring in the two most prominent systems. Two new systems have been found, one having the same lower state as those previously reported and the other forming a double array. The latter has been tentatively assumed to be due to $\mathrm{As}_2^{}{}_{}{}^{+}$.