DENSITY-FUNCTIONAL THEORY - AN EFFECTIVE THEORETICAL TOOL FOR THE STUDY OF SIGMA-RADICALS

The structures, harmonic force fields, and hyperfine coupling constants of a number of representative sigma radicals have been investigated by the density functional approach including nonlocal corrections. Scaling of CH bond lengths and stretching constants leads to accurate structures and force fields. Hyperfine coupling constants reach, at least, the level of the most sophisticated conventional post-Hartree-Fock models. This suggests that the density functional approach is a promising theoretical tool for the study of relationships between structure and spectroscopic properties of large free radicals. (C) 1994 John Wiley & Sons, Inc.