Heitler, Herzberg Observed that Nitrogen Nuclei Obey Bose

In their historical article “Enrico Fermi in Rome, 1931–32” (Physics Today, June 2002, page 28 ), authors Hans A. Bethe and Henry Bethe state, “One of Fermi’s colleagues observed the band spectrum of gaseous nitrogen and found that nitrogen nuclei obey Bose statistics.” I offer a clarification. Indeed, Franco Rasetti observed the rotational Raman spectrum of gaseous N₂ in 1929. However, Walter Heitler and Gerhard Herzberg were the ones who recognized the difference in intensity alternation of rotational lines from that in H₂: Even-numbered lines were more intense than the odd-numbered lines. Heitler and Herzberg therefore concluded that N nuclei obey Bose statistics. ¹ The explanation was, of course, only clarified after the discovery of the neutron three years later.