ANALYTICAL EXPRESSIONS FOR THE N-ORDER MOMENTA OF CHARGE-DISTRIBUTIONFOR IONS

In this work a family of four analytic expressions for the n-order mom enta of the charge distribution for ions, [r(n)], depending on three, two, or one parameters will be presented. These expressions are derive d through the use of electronic charge densities obtained from a famil y of four analytical potentials. The parameters in the expressions wer e obtained for ions in the ground state from helium to uranium isoelec tronic sequences. The use of these parameters allows to find analytica l expressions for the [r(n)] as functions of the nuclear charge, Z, on ly. Finally, the results obtained are compared with results computed b y different methods. (C) 1998 Elsevier Science Ltd. All rights reserve d.