THEORETICAL-STUDY OF THE INTERACTION OF ALKALI-METAL ATOMS WITH CO2

Chemical interaction and coordination modes of CO2 with alkali metals M (M = Li, Na, K) have been investigated by means of density functiona l theory (DFT). Both gradient-corrected Perdew-Wang-Perdew and hybrid B3LYP exchange-correlation functionals were employed. Surprisingly, th e behavior of Li is different from that of Na or K. For Li-CO2 the abs olute minimum corresponds to a C-2v structure where the CO2 molecule i s rather distorted, and two other minima were found, a linear M-O-C-O and a C-s structure where M is coordinated to C but where CO2 remains almost linear. For Na and K the bond is always weak and the binding en ergies Lie near the limit of the interactions that can be described by means of DFT. (C) 1998 Elsevier Science B.V. All rights reserved.