  Generalized oscillator strengths (GOS's) for the Na $3s -3p$ transition have
been investigated using the spin-polarized technique of the random phase
approximation with exchange (RPAE) and the first Born approximation (FBA),
focussing our attention on the position of the minimum. Intershell correlations
are found to influence the position of the minimum significantly, but hardly
that of the maximum. The RPAE calculation predicts for the first time the
positions of the minimum and maximum at momentum transfer, $K$ values of 1.258
a.u. and 1.61 a.u., respectively. The former value is within the range of
values extracted from experimental measurements, $K=1.0-1.67$ a.u.. We
recommend careful experimental search for the minimum around the predicted
value for confirmation.
