Resistivity peculiarities in systems with lattice distortions

We study a molecular lattice Hamiltonian in which polaronic charge carriers interact with non linear potentials provided by local atomic fluctuations between two equilibrium sites. The path integral formalism is applied to select the class of atomic oscillations which mainly contributes to the partition function and the electrical resistivity is computed in a number of representative cases. Non metallic resistivity behaviors are found at temperatures above $\simeq 100K$.