The diagonal term does not appear in the excitation generation and the single excitations are not modified at all. Only the double excitations of exchange type are actually modified and their respective PCHB weight (equation 12) becomes |g AIBJ -g AJBI + J|. If we additionally assume spatial orbitals, i.e. g AIBJ = g aσ,iτ ,bµ,jν = g a,i,b,j δ στ δ µν , we finally get |J -g ijji |.