Given the small values of the torsional angle fluctuations Δ𝜃 𝑘 (𝛥𝜃 𝑘 = 𝜃 𝑘 -𝜃 𝑘,𝑓𝑟𝑜𝑧𝑒𝑛 ) in the constrained environment of the bulk polymers, only the leading term of the non-local electron-phonon coupling is included in the present study. Thus, the effective non-local electron-phonon coupling term in the total Hamiltonian can be represented as,