https://www.selleckchem.com/pr....oducts/NVP-BHG712.ht
Based on this finding, we give a rigorous proof of fulfillment of BT for the alternative o → o excitation, which takes in the helium atom the form S11 → S31, where both the initial and excited states are treated as arising from the same open-shell configuration 1s12s1, and the state S31 is described by the symmetry-adapted ROHF wave function Ψ(S31) = [Ψ(S21) - Ψ(S01)]/2. The new formulation of BT obeys all the necessary variational and symmetrical conditions, and its validity is illustrated by the results of computations of atom He a