Letter for the pressure effects on the electrostatic polarizability and dispersive binding of off-center polarons in ionic and molecular systems

The question is raised about the pressure effects on the polarizability and dispersive binding in ionic and molecular systems. As an example we take the effect of hydrostatic pressure on the energy gap of phonon-coupled two-level systems. Assuming a positive pressure coefficient for the gap, we predict a gradual transition from small vibronic polarons to large polarons as the pressure is increased at constant coupling energy of a two-level system. Concomitantly, the universal dispersive binding degrades from strong at low pressure to weak at high pressure as the system evolves from soft condensed matter to hard condensed matter. Implications are discussed on the development of stellar substance at the early stages of the Universe.