Recent Developments in Configuration Interaction and Density Functional Theory Calculations of Radical Hyperfine Structure

Publisher Summary This chapter investigates two fundamentally different, yet complementary routes to computational studies of radical hyperfine structures. The role and importance of higher than double excitations in the configuration expansions has been elucidated by means of detailed case studies on a number of first row atoms, as well some selected molecular systems. The chapter later explored an alternative route to the calculation of radical hfs—namely the DFT-based approaches. Future applications of the DFT based hfcc calculations will involve extending the sets of systems into areas, such as surface chemistry, biophysics, and large transition metal complexes, where MRCI approaches again will serve as an extremely important tool for calibrating the calculations of the larger systems, to reveal possible pitfalls and explain deviations when these occur.