Spin coupling and resonance

The resonating block localize wave function (RBLW) method is introduced, a resonating modification of the block localized wave functions introduced by Mo et al. [Mo, Y.; Peyerimhoff, S. D. J. Chem. Phys. 1998, 109, 1687].This approach allows the evaluation of resonance energies following Pauling’s recipe. The method is tested on two model molecules, hexagonal H6 and benzene. Calculations have been done with (local) and without local restrictions (delocal). Resonance energies for both molecules have been obtained for each type of calculation, in agreement with Pauling’s concept. From a comparison of the resonance energies obtained from RBLW and standard valence bond calculations, the resonating block localize wave functions prove to yield resonance energies close to standard valence bond delocal calculations.