PROTON-TRANSFER IN IONIC HYDROGEN-BONDS

Correlated electronic structure calculations, coupled with atoms in mo lecules analysis, have been employed in a study of proton transfer in ionic hydrogen bonds. The isoelectronic series FHF-, H3O2-, H5O2+, and N2H7+ are used as models for such processes. Calculations at the MP2/ 6-311++G* level on the minimum energy structure and the transition st ate for proton transfer give an estimate of the barrier to proton tran sfer. Decomposition of the resulting charge distributions and energeti cs using Bader's techniques provides a deeper understanding of the ele ctronic factors determining proton transfer barriers. It also indicate s a fundamental difference between anionic and cationic hydrogen bonds .