Photoinduced absorption measurements of triplet states in poly(p-pyridine)

We report cvv photoinduced absorption (PIA) measurements of poly(p-pyridine) (PPY). Three correlated, induced features are found below the π → π* transition. All have a strong temperature dependence and similar lifetimes of ca 10 ms. Comparing to ZINDO/S-CI calculations of the triplet manifold we find good agreement and so conclude that the PIA represents transitions within the triplet manifold. However, as yet we have not been able to definitively measure a ν−1 chop rate dependence for the PIA signals indicative of monomolecular recombination.