Ultrafast electronic relaxations from the S3 state of pyrene

Jennifer A. Noble, Christian Aupetit, Dominique Descamps, Stéphane Petit, Aude Simon, Joëlle Mascetti, Nadia Ben Amor, Valérie Blanchet

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4 Scopus citations


The ultrafast relaxation occurring in pyrene upon excitation at 4.68 eV was studied in a supersonic gas-jet fs pump-probe experiment. Mass spectrometry and velocity map imaging of photoelectrons produced by probing via multiphoton ionisation at 800 nm reveal that the initially prepared wave packet exhibits a fast relaxation (<80 fs), followed by a slower one of 200 fs. By comparing the propensity rules of photoionisation observed at one color with ab initio calculations, we tentatively assign these two timescales to a first internal conversion to the dark bB3g state followed by a second one to the long lived aB2u first excited state. Vertical excitation energies determined using ab initio Multi-State Complete Active Space 2nd order Perturbation Theory (MS-CASPT2), as well as oscillator strengths between several electronic states, are reported.

Original languageEnglish
Pages (from-to)14111-14125
Number of pages15
JournalPhysical Chemistry Chemical Physics
Issue number26
StatePublished - 2019
Externally publishedYes


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