A non-perturbative treatment of the generalized Su-Schreiffer-Heeger   Hamiltonian on a dimer
  Starting from the Hamiltonian for a dimer which includes all the electronic and electron-phonon terms consistent with a non-degenerate orbital, by a sequence of displacement and squeezing transformation we obtain an effective polaronic Hamiltonian. The renormalized electronic interactions differ from the results of semiclassical or perturbative treatments. The properties of the variationally determined ground state of two particles in the orbital are discussed for variable dimer length in the adiabatic limit. 
M. Cococcioni (International School for Advanced Studies-SISSA,   Grignano(TS), Italy) and M. Acquarone (GNSM,INFM, Universi...