Polyradical character assessment using multireference calculations and comparison with density-functional derived fractional occupation number weighted density analysis
Reed Nieman, Jhonatas R. Carvalho, Bhumika Jayee, Andreas Hansen, Adélia J. A. Aquino, Miklós Kertész, Hans Lischka
Abstract
have been considered as well. After adjustment of the literature-recommended finite temperatures, a very good, detailed agreement between unpaired density and FOD analysis is observed which is also manifested in excellent statistical correlations. The other two descriptors also show good correlations even though the absolute scaling is not satisfactory. A new linear fit of FOD data to the MR-AQCC reference values leads to an improved regression relation for determining the recommended finite temperature value in dependence of the Hartree-Fock exchange. This provides the basis for fast and reliable assessment of the biradical character of many classes of PAHs without the need for performing computationally extended MR calculations.