Near-infrared dynamics of photoexcitations in a substituted polyacetylene

Near-infrared (0.52–1.37 eV) transient spectra of a substituted polyacetylene, poly[[(o-trimethylsilyl)phenyl]acetylene], were measured with a time-resolution better than 300 fs. Whole spectra of hot self-trapped excitons and relaxed, overall neutral pairs of oppositely charged, spatially confined soliton-antisoliton were measured deep in the band gap. The confinement parameter γ=0.23±0.07 and on-site Coulomb repulsion ${\mathit{U}}_0$=2.8±0.4 eV were determined from the results.