Ab initio theoretical investigation of the hydrogen-, lithium-, sodium- and potassium cation affinities of the XY (X,Y = H, Li, Na, K) alkali dimers

Ab initio variational calculations were performed for the study of ground s tate properties of the XYZ(+) (X,Y,Z = HI, Li, Na, K) homonuclear and heter onuclear cationic alkali trimer ions. Their molecular geometry was determin ed and all the discussed systems were predicted to be stable in the gas pha se. The hydrogen-, lithium-, sodium- and potassium cation affinities, CA, o f the XY (X,Y = H, Li, Na, K) alkali dimers were treated. According to the theoretical investigations-considering the mentioned cation affinities of t he M = H-2, LiH, Li-2, NaH, NaLi, Na-2, KH, LiK, NaK dimers-the relations i n the series are: CA(M...H+) > CA(M...Li+) > CA(M...Na+) > CA(M...K+). (C) 2000 Elsevier Scie nce B.V. All rights reserved.