@article{78116317b2b64f6d8895ea6b8ce7590e,

title = "Quantum lattice fluctuations in nearly degenerate quasi one-dimensional polymers",

abstract = "It has been shown that the linear and nonlinear optical behaviors are quite different for degenerate and nondegenerate polymers. Quantum lattice fluctuations are believed to play an important role in the understanding of these optical properties. In this work, we study the quantum lattice fluctuations in a nondegenerate conjugated polymer by means of a modified Su-Schrieffer-Heeger-type model Hamiltonian. We first integrate out the electronic variables of the partition function and obtain an effective phonon action. Then an equation for the phonon order parameter is derived within a one-loop approximation. We find that the quantum lattice fluctuations is reduced by the nondegenerate ground state, especially in the weak electron-phonon coupling. This result is compatible with the optical properties of degenerate and nondegenerate polymers.",

keywords = "Electron-solid interactions, Polyacetylene and derivatives, Structural phase trasitions",

author = "Wu, {C. Q.} and Y. Kawazoe",

note = "Funding Information: It can be seen that in strong electron-phonon coupling region the ground-state degeneracy can be ignored since the order parameter Ai should be much larger than the value of At of nondegenerate polymers. However, the degeneracy becomes important for weak electron-phonon interaction systems. By calculating the reduction (Ai - A,d)/A,d s Aad is the value of hi at adiabatic limit, we find that in the limit of weak e-p interaction the reduction of the lattice dimerization by quantum fluctuations will be zero for nondegenerate polymers. However, the reduction is 100% for a degenerate polymer. It means the lifting of the degenerate ground states greatly suppresses the quantum lattice fluctuations. This is compatible with the linear optical absorption properties of degenerate {\textquoteleft}and nondegenerate polymers since it is believed that the quantum lattice fluctuation accounts for the absorption tail extending into the energy gap. One of the authors (C.Q.W.) is grateful to the Shanghai Qi-Ming-Xing Plan for Young Scientists and the National Natural Foundation of China for their supports.",

year = "1997",

month = mar,

day = "15",

doi = "10.1016/s0379-6779(97)80190-7",

language = "English",

volume = "85",

pages = "1151--1152",

journal = "Synthetic Metals",

issn = "0379-6779",

publisher = "Elsevier BV",

number = "1-3",

}