Properties of the phosphonic-acid molecule and the proton transfer in the phosphonic-acid dimer

Density-functional calculations of the phosphonic-acid molecule have been performed. We are presenting the bonding information and compare different exchange-correlation functionals, that have been used. Moreover, the proton affinity of phosphonic-acid has been computed. Finally, we have investigated the proton transfer in a protonated dimer. The activation energy of this process is strongly depending on the intermolecular distance of the participating phosphonic-acid molecules.