2006/03/10 by T. Tsuchiya, Takashi Tsuchiya, B. O. Roos +1
Physics and Astronomy · Engineering · Materials Science · #Advanced Chemical Physics Studies #Molecular Junctions and Nanostructures #Catalytic Processes in Materials Science
paper · doi:10.1080/00268970500417135
The spin-forbidden reaction of Fe(CO)(4)+CO -> Fe(CO)(5) has been investigated with multiconfigurational quantum chemical methods (CASSCF/CASPT2). The structure of the minimum energy crossing point ( MECP) between the singlet and triplet energy surfaces as well as the equilibrium structures of Fe(CO)(5) ( a singlet state) and Fe(CO)(4) ( a triplet state) has been determined. The partition rational function (RF) method has been used for the geometry optimization together with approximate numerical gradient vectors and Hessian matrices. The Fe-CO bond angles of the MECP are between those of the equilibrium structures of the ground states of Fe(CO)(5) and Fe(CO)(4), while a considerable extension of the Fe-CO bonds have been shown to occur at the MECP when transferring from the triplet ( reactant) PES to the singlet ( product) PES. It has also been shown that the MECP prefers to have a Cs symmetry structure with the incoming CO tilted rather than a C-2v structure with Fe and the incoming CO on a straight line.