Binding Energy ofLi7

A first-order Hartree calculation based upon a reasonable set of nuclear constants yields only one-third the known binding energy of ${\mathrm{Li}}^7$. It is of interest to know whether this discrepancy is a real failure of assumed nuclear forces or merely a result of an inadequate method of calculation. The present note reports the effect of including higher orders in the perturbation treatment. In the final result about half the discrepancy remains and may be attributed to the exchange forces here assumed.