ELECTRONIC-STRUCTURE AND MOLECULAR-DYNAMICS OF NA2LI

Following the first report (Mile, B., Sillman, P. D., Yacob, A. R. and Howard, J. A., 1996, J. chem. Sec. Dalton Trans, 653) of the EPR spec trum of the mixed alkali-metal trimer Na2Li a detailed study has been made of the electronic structure and structural dynamics of this speci es. Two isomeric forms have been found: one of the type, Na-Li-Na, of C-2v, symmetry and another, Li-Na-Na, of C-s symmetry. Also, there are two linear saddle points which correspond to 'inversion' transition s tructures, and a saddle point of C-s symmetry which connects the two m inima. A molecular dynamics investigation of these species shows that, at the temperature of the reported experiments (170 K), the C-2v mini mum is not 'static', but undergoes quite rapid inversion. At higher te mperatures the C-2v minimum converts to the C-s form, but by a mechani sm very different from that suggested by minimum energy path considera tions.