Coriolis coupling constants and inertial defect of B₂F₄ by ab initio calculations and the iterative method

Structural parameters, harmonic frequencies, and force constants of B₂F₄ were obtained in internal coordinates from ab initio RHF calculations with the 6-311G* basis set. The results obtained are used to calculate the Coriolis coupling constants and the inertial defect for ¹⁰B₂F₄ and ¹¹B₂F₄ and to compare these values with those obtained by using the autoconsistency method. Both the ab initio and the iterative force fields, despite some significant differences, reproduce the vibrational wave numbers equally well and yield nearly the same Coriolis coupling constants and inertial defects. The calculated inertial defects for ¹⁰B₂F₄ and ¹¹B₂F₄ are -0.942 and -0.919 amu Ų, respectively.