Theoretical Calculations of The Second Hyperpolarizability inSubstituted meta-xylylene Diradicals

Abstract: The electronic state ordering is calculated in substituted meta-xylylene diradicals for reproduction and comparison of results previously published by other authors. The second hyperpolarizability, γ, is calculated in the same systems using different methods. The diradical character is calculated for comparison and discussion of the γ values. The obtained electronic state ordering agrees qualitatively with previous findings. The γ values obtained from the finite-field method, which are related to the diradical character, agree with theory. The γ values obtained from the sum-over-states method, which relate to the vertical state ordering, are unsatisfactory.