THEORETICAL-STUDY OF CHARGE-TRANSFER IN GRAPHITE-INTERCALATION COMPOUNDS

A theoretical method of determination of charge transfer is proposed. This method is based on the minimization of the total energy as a func tion of charge transfer. The compounds studied are in the form M(+x)(C (-x/6))6 or M(+x)(C(-x/8))8 where M represents the donor intercalate s pecies (M = Li, K, Ca, Rb, Sr, Cs, Ba, Sm, Eu and Yb) and x the fracti on of electron charge transferred from the intercalate to the graphite . The energy consists of three contributions: E(kinetic), E(potential) (coulombic+exchange) and E(Madelung). These three contributions are c alculated as a function of x. The value of x giving the most stable st ate (minimum of energy of the compound) is defined as the charge trans fer.