Abstract: We study the influences of the temperature on the energy-band structure for the Holstein molecular-crystal model.We show that the energy-band width and the energy-gap width of a solid are relevant to both the interaction between an electron and thermal phonons and to thermal expansion.For a one-dimensional Li atom lattice chain,under the chosen parameters,the width of the 1s and 2s energy bands narrows as the temperature increases and the energy-gap width between the two bands widens.These results agree qualitatively with those observed experimentally.Studying temperature dependence of the energy-band structure is of great importance for understanding optical and transporting characteristics of a solid.

Key words: temperature dependence, energy-band structure, thermal phonon, thermal expansion