Electronic states and potential energy surfaces of the tungsten trimer (W3)

The equilibrium geometries and bending potential energy surfaces of twelve electronic states of the tungsten trimer (W3) are obtained by the complete active space multi-configuration self-consistent field (CAS-MCSCF) followed by multi-reference configuration interaction computations (MRSDCI) that included up to 1.8 million configurations. The spin-orbit effects were also incorporated using the relativistic CI (RCI) technique. Both electron correlation and spin-orbit effects were found to be significant for W3. The electronic states of W3 exhibit very short W-W bonds with dπ-dπ and pπ-pπ bonding.