An anomaly in the isotopomer shift of the hyperfine spectrum of LiI

A high-precision examination of the hyperfine spectrum of (LiI)-Li-6 in comparison with (LiI)-Li-7 shows a shift in the iodine nuclear electric quadrupole moment that cannot be accounted for by a model in which the electric field gradient at the iodine site is assumed to depend only upon the internuclear distance between Li and I. The other hyperfine interactions are consistent between the two isotopomers, including the previously reported electric hexadecapole interaction of the iodine nucleus. (c) 2005 American Institute of Physics.