Existence of weakly bound states for metal-benzene molecules confirmed from a long-range model
Résumé
A long-range model adding a repulsive term from SCF calculations and an attractive term from dispersion evaluated in an oblate spheroidal formalism is proposed for the interaction energy between a transition metal atom and a benzene molecule. An analytical form is derived for the total energy of MC[6]H[6] complexes versus the distance R between M and the benzene center of mass. Ground state weakly bound (D[e] ∼ 200-600 K) at long range (R[e] ∼ 4-4.5 A) are obtained for the three systems ScC[6]H[6], VC[6]H[6] and NiC[6]H[6], confirming the first evidence of these structures previously pointed out from both electric dipole measurements and CASSCF-MRCI calculations.