SELF-TRAPPING DYNAMICS OF EXCITONS ON A ONE-DIMENSIONAL LATTICE

Lattice relaxation dynamics of one-dimensional excitons coupled with a n optical lattice vibration mode is studied using molecular dynamics t echniques. By investigating the time-evolution of the wave-function an d other physical properties, it is found that not only the wavefunctio n of the relaxed state, a self-trapped exciton (STE), but also the rel axation dynamics changes by varying the strength of the electron-phono n interaction. Hence we can classify STEs into ''large'' STEs and ''sm all'' STEs by means of the difference in physical properties. Such dif ference is more enhanced for excitons than for polarons, since both th e translational motion and the relative motion of the electron and hol e is affected in excitons. Dispersion in the phonon frequency also pla ys an important role in this classification. Optical properties, the S tokes shift and the peak shift of photoinduced absorption, are also ca lculated.