Excitation dependence of the subpicosecond dynamics of excitons and polarons in the MX chain solid PtCl

We have measured the subpicosecond photoinduced absorption for the MX chain solid PtCl. For excitation into the tail of the exciton absorption a state is generated with a lifetime of 100–200 ps, and is associated with the lowest even parity exciton. For lower energy pump, our results are consistent with excitation of intrinsic polarons, which decay to the ground state in about 1 ps. Excitation well above the exciton band edge may result in the formation of polarons and excitons.