No abstract

The detailed mechanism of the interaction of the radical cation ABTS•+ with a number of food acids (gallic, ferulic, caffeic, vanillic, cinnamic, syringic, p-coumaric) is revealed by means of the DFT calculations. It is shown that the interaction between the neutral molecules of the studied food acids and ABTS•+ does not lead to any charge transfer from these molecules onto ABTS•+. The almost complete conversion of the ABTS radical cation into its diamagnetic derivative occurs due to the interaction of one of the sulphonic groups of ABTS•+ with the acid anions through the formation of the corresponding intermolecular hydrogen bond.

No abstract

The results of ab initio calculations of the adiabatic potential energy surfaces for the proton-bound [FHF]- system at different F-F distances have been rationalized in the framework of the vibronic theory. It is shown that the instability of the symmetric D∞h structure at increased F∙∙∙F distances and the proton displacement to one of the fluorine atoms is due to the pseudo Jahn–Teller mixing of the ground 1Σg electronic state with the lowest excited state of 1Σu symmetry through the asymmetric σu vibrational mode.