Asymptotic dispersion energies from distributed polarizabilities

A new algorithm is proposed for calculations of distributed molecular polarizabilities. In contrast to published algorithms, it virtually eliminates the charge-flow terms that result in a slower than inverse sixth power decay of dispersion energy whereas the remaining terms have unique and physically reasonable values. Dispersion energies computed from these polarizabilities are very close to unexpanded dispersion energies in the region of small charge overlap. The method is expected to provide reference data for development of dispersion functions used in simulations of biomolecules and in dispersion-supplemented density-functional approaches.