MOLECULAR SIMILARITY BASED ON INFORMATION ENTROPIES AND DISTANCES

A similarity index based on the concept of an information distance is evaluated for a series of diatomic molecules. The results show that th e momentum space information distance is a good indicator of the exten t of charge separation present in a molecule. The Shannon entropy in p osition space is shown to decrease with increasing charge separation a nd as such is presented as a measure of the structure or extent of ele ctron localization in a system. The concept of a local Shannon entropy over an atomic basin is introduced and it is shown how this quantity may be used to examine the local behavior of electron densities. (C) 1 998 American Institute of Physics. [S0021-9606(98)03113-4].