Observation of hyperfine structure in the electronic Raman spectrum of atomic iodine

Stokes Raman scattering from atomic iodine has been observed for the first time by means of argon ion laser excitation at 457.9 nm. The same laser also served to produce atomic iodine by photodissociation of 127I35Cl. With high spectral resolution the hyperfine structure of the 2P1/2←2P3/2 atomic iodine transition could be partially resolved. A theoretical simulation of the total Raman band, which consists of eight allowed F2-F1 Raman transitions, shows excellent agreement with the observed spectrum. It is shown that the Raman scattering in iodine originates completely from the quadrupole component of the atomic scattering operator.