Calculation of the lifetime of a Davydov soliton at finite temperature

The standard Davydov Hamiltonian can be partially diagonalized using a method due to Eremko, Gaididei, and Vakhnenko. The complete Hamiltonian in this partially diagonalized form, however, includes a term omitted by these authors. Using this term in a first-order perturbation theory calculation results in an estimate of the lifetime of a Davydov soliton at finite temperatures. The lifetime at 300 K is on the order of ${10}^{\mathrm{-}12}$ s for parameters appropriate for the α-helical protein molecule. This is too short to be useful in biological processes.