By the methods of photographic photometry, the alternating intensities in emission of the $\Delta v=0\mathrm{}$ sequence of the Fulcher bands of deuterium have been investigated in order to determine the nuclear spin. The alternation of intensities was determined for the $P$, $Q$ and $R$ branches of each of the 5 bands studied. The average value of $\frac{g_s}{g_a}$ obtained from 4 plates is 1.97±0.03. This value agrees best with the theoretical ratio of 2 and a consequent nuclear spin of 1. Since the even rotational levels are more intense than the odd levels, the nucleus obeys Bose-Einstein statistics.

• Received 28 May 1934

DOI:https://doi.org/10.1103/PhysRev.46.95