Giant mass sensitivities of molecular transitions supported by asymmetric double-well potentials

ABSTRACT Energy splittings of tunnelling molecular states localized on different sides of asymmetric double-well potentials exhibit a profound dependence on reduced molecular mass. They therefore appear greatly promising as tools for investigating possible cosmological variation in the proton-to-electron mass ratio, usually denoted by $\mu$. In the present article, this hitherto overlooked possibility is examined using model calculations based on a set of realistic model potential energy functions. The calculations show that the probed states can support a large number of transitions possessing much greater mass sensitivities than their currently used counterparts supported by symmetric double-well potentials.