Scaled particle theory in calculation of E(dispersive-replusive)



Dear all,
 I have a question about the paper about scaled particle theory in
 Chemical Reviews, 1976, Vol.78, No.6, 717-726 written by Robert A.
 Pierotti.
 In page 720-721, Pierotti dealed with the G(interaction) by
 ingetration of e(r) 4 pi r^2 g dr. Is this equation derived from
 scaled particle theory?
 Thank you for your help and attenion.
 I am looking forward to your reply.
 Best regards,
 Patrick