Effective hyperfine Hamiltonian in homonuclear diatomic molecules. Application to the B state of molecular iodine

Abstract

The effective hyperfine Hamiltonian is studied in the case of homonuclear diatomic molecules, using irreducible tensorial algebra. The second order perturbation terms due to the magnetic dipole and electric quadrupole Hamiltonian are calculated in a compact form. These calculations are applied to the B state of molecular iodine : the experimental values of the scalar and tensorial spin-spin coupling constants are interpreted. Moreover it is shown that the recently published magnetic octupole coupling value for the B state is unrealistic and also that some other terms must be introduced in the hyperfine Hamiltonian