Theoretical calculations on the reactions of NO2 with Sc, Ti and V

Density functional calculations have been performed to describe the ground- state reactions between NO2 and Sc, Ti and V atoms. We have obtained smooth energy curves along the reaction coordinate and found no barrier. The reac tion products form a quite strong MO-NO complex via a 1 delta-2 pi * bond a t the end of the reactions. The reactions are initiated by mutual electron donations between the metal atom and the NO2 molecule. Considerable 4s-3d h ybridization takes place continuously on the metal atoms in the following s tages to facilitate the formation of the ground-slate metal oxides in the c ase of Ti and V. For Sc the calculations revealed that the final complex re quires formation of the lowest excited ScO state compensated in energy by t he large stability of the complex. To elucidate the complete reaction mecha nism ingredients of both the so-called electron transfer and surface crossi ng models have to be invoked. (C) 1998 Elsevier Science B.V. All rights res erved.