Ab InitioCalculation of Hyperfine and Magnetic Parameters in theI2BState

A simple analytic calculation of magnetic and hyperfine constants of molecular iodine in the $B{}_{}{}^3{}_{}{}^{}\Pi _{0^{+}\mathrm{u}}^{}{}_{}{}^{}$ state is carried out. The calculation is based on simple physical ideas which are well suited to represent precisely molecular states close to their dissociation limit. Thus the method is quite general. The agreement between theory and experiment for the ${\mathrm{I}}_2$ $B$ state is good.