Abstract:
This paper reflects a theoretical study of double proton transfer in formic acid dimer (as a model) using the Pseudo Jahn-Teller Effect (PJTE) theory and ab initio calculations of electronic structure and adiabatic potential energy curves. The estimated PJTE parameters demonstrate the instability of the highly symmetric nuclear configuration of the studied dimer with respect to the displacement of the protons from the central position to one of the formic acid molecules. The reason for this instability is the PJT coupling between the ground 1Ag and excited 1B1g electronic states.