Excited-State Vibrational Coherence in Perylene Bisimide Probed by Femtosecond Broadband Pump-Probe Spectroscopy

Minjung Son, Kyu Hyung Park, Min Chul Yoon, Pyosang Kim, Dongho Kim*

*Corresponding author for this work

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Broadband laser pulses with ultrashort duration are capable of triggering impulsive excitation of the superposition of vibrational eigenstates, giving rise to quantum beating signals originating from coherent wave packet motions along the potential energy surface. In this work, coherent vibrational wave packet dynamics of an N,N′-bis(2,6-dimethylphenyl)perylene bisimide (DMP-PBI) were investigated by femtosecond broadband pump-probe spectroscopy which features fast and balanced data acquisition with a wide spectral coverage of >200 nm. Clear modulations were observed in the envelope of the stimulated emission decay profiles of DMP-PBI with the oscillation frequencies of 140 and 275 cm-1. Fast Fourier transform analysis of each oscillatory mode revealed characteristic phase jumps near the maxima of the steady-state fluorescence, indicating that the observed vibrational coherence originates from an excited-state wave packet motion. Quantum calculations of the normal modes at the low-frequency region suggest that low-frequency C-C (C-C) stretching motions accompanied by deformation of the dimethylphenyl substituents are responsible for the manifestation of such coherent wave packet dynamics.

Original languageEnglish (US)
Pages (from-to)6275-6282
Number of pages8
JournalJournal of Physical Chemistry A
Volume119
Issue number24
DOIs
StatePublished - Jun 18 2015

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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