Posted by Bernd Schimmelpfennig on May 08, 2006 at 16:44:33:
In Reply to: Question about spin-orbit coupling in the manual posted by Wenli Zou on March 09, 2006 at 04:41:18:
The Douglas-Kroll keyword switches on the scalar relativistic terms only, they are thus included from the beginning by changing the scalar 1-electron integrals. The spin-orbit operator is a dfferent topic and two flavors are implemented: The Breit-Pauli operator and the no-pair spin-orbit operator to be used together with the scalar Douglas-Kroll term.
Thus by switching on the SO-operator and Douglas-Kroll at the same time, there is no double-counting but simply the use of Douglas-Kroll for scalar relativity and a corresponding SO-operator.