Effects of the Bending Mode of Vibration on the Hyperfine Structure of ICN

The bending mode of vibration in ICN introduces an asymmetry in the electric field gradient at the iodine nucleus. From an observed variation in the $l$-type doublet splittings of various hyperfine components for the $v_2=1\mathrm{}$ state, the asymmetry parameter is determined as $\eta =0.0087\mathrm{}$. It is found that the measured splittings can be accounted for fully by including second-order perturbation terms arising from field asymmetry. The ratio $\frac{{\mathrm{}\left(\mathrm{eqQ}\right)\mathrm{}}_{v=0\mathrm{}}}{{\mathrm{}\left(\mathrm{eqQ}\right)\mathrm{}}_{v_2=1\mathrm{}}}$ is measured as 1.0039. This ratio and the observed value of $\eta$ are discussed in terms of the molecular bending and I-C bonding electrons.