I think you can find the answer to your question in the post at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg02807.html > I have qst about "sp" calculation with "so" interaction : > > If we are able to run "sp" with "so" ,and calculating all v element > matrix by chanching kpot to 1 in case.inso ,why we dont'n have "x > lapwso -dn" ?