Spin Density in NPA
Note about how to read spin density from Gaussian pop=NBO output
Gaussian use NBO version 3 by default that does not explictly print out the spin density in the out file. ref
The .out file contains 3 segment of NPA table, the last two is treating alpha and beta orbitals seperately.
The spin density can be calculated by:
$TOTAL_{\alpha} - TOTAL_{\beta}$
the two terms are from alpha and beta table.