Electronic structure and molecular dynamics of Na2Li

Abstract

Following the first report (Mile, B., Sillman, P. D., Yacob, A. R. and Howard, J. A., 1996, J. chem. Soc. Dalton Trans, 653) of the EPR spectrum of the mixed alkali-metal trimer Na2Li a detailed study has been made of the electronic structure and structural dynamics of this species. Two isomeric forms have been found: one of the type, Na–Li–Na, of C2v, symmetry and another, Li–Na–Na, of Cs symmetry. Also, there are two linear saddle points which correspond to ‘inversion’ transition structures, and a saddle point of C s symmetry which connects the two minima. A molecular dynamics investigation of these species shows that, at the temperature of the reported experiments (170 K), the C2v minimum is not 'static', but undergoes quite rapid inversion. At higher temperatures the C minimum converts to the Cs form, but by a mechanism very different from that suggested by minimum energy path considerations.