TOWARDS THE ACCURATE COMPUTATION OF PROPERTIES OF TRANSITION-METAL COMPOUNDS - THE BINDING-ENERGY OF FERROCENE

Recently published ab initio computations on ferrocene in the framewor k of coupled-cluster as well as multireference perturbation theory are exploited to obtain a theoretical best estimate of 655 +/- 15 kcal/mo l for the heterolytic bond disruption enthalpy. This best estimate was obtained by establishing the complete atomic orbitals basis set limit at the level of single-reference second-order perturbation theory, an d computing corrections for relativistic effects, semicore (3s/3p) ele ctron correlation effects, vibrational zero-point energy corrections, and structural relaxation energies of the fragments. Agreement with th e experimental value of 635 +/- 6 kcal/mol is unsatisfactory.