The majority of environmental processes are essentially based on chemical transformations that involve either electron, or proton transfer, or both. Therefore, revealing the micro-mechanisms of the latter is crucial for the understanding and possible manipulation of these processes. On the other hand, the vibronic coupling theory, mostly the pseudo-Jahn-Teller effect (PJTE), as the only source of spontaneous symmetry breaking of high-symmetry configurations of polyatomic systems [1], was shown to control the proton transfer between two molecular systems, often termed as the Hydrogen (H) bond [2-4]. This, in turn, allowed us to estimate the main parameter of the H-bond, the energy barrier for the proton transfer between the interacting molecular systems. In this presentation we show how the PJTE influences the energy barrier for the proton transfer, in general, with several illustrative chemical processes as examples. These include a number of proton-bounded 30entral such as (pyridine)2H+, (butanone)2H+, and other systems. Particular attention is paid to intramolecular proton transfer in excited states (ESPT) using the example of a neutral malonic aldehyde molecule, in which the transfer of a proton occurs through the intramolecular H-bond involving a five-membered ring. This process is compared with the proton transfer in similar systems in which the ring size changes to four and six and in which the systems have a common negative charge. It is shown that in all the considered cases the low-barrier hydrogen bond can be described within the framework of the pseudo-Jahn-Teller effect. The functional dependence of the potential energy on the instability coordinate, following from the PJTE theory, with parameters estimated using quantum chemical calculations, can serve as a parametrized analytical model of the adiabatic potential, which can be used to simulate the proton transfer process in such systems.