Novel insights on the vibronic transitions in free base meso-tetrapyridyl porphyrin

ORAL

Abstract

We present novel results on the free base 5,10,15,20-meso-tetra(pyridyl)-21H,23H-porphyrin (H2TPyP). This molecule presents complex electronic and vibrational properties and in spite of the vast literature reporting the transitions observed in its absorption and fluorescence spectra, a more accurate interpretation has been kept elusive. In particular, we show that the molecule’s Q-band is clearly developed into many electronic and vibronic transitions, whose the well-known “four orbital model” finds it difficult to reconcile. Using distinct spectroscopy techniques, we conclude that both Qx- and Qy-bands comprise, in fact, two quasi-degenerated electronic states together with their respective vibronic progressions each. The analysis of the Huang-Rhys factors and complementary time- and polarization-resolved measurements reinforce the need for the proposed Q-band multi features remodeling.

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Presenters

  • Keshav Sharma

    Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama, United States, University of Alabama

Authors

  • Jefferson Marcio Sanches Lopes

    Graduate Program in Physics, Federal University of Para, Belem, PA, Brazil, Federal University of Pará

  • Keshav Sharma

    Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama, United States, University of Alabama

  • Renato Neiva Sampaio

    Department of Chemistry, The University of North Carolina at Chapel Hill, Murray Hall, Chapel Hill, NC, United States, University of North Carolina at Chapel Hill

  • Alzir Azevedo Batista

    Department of Chemistry, Federal University of Sao Carlos, Sao Carlos, SP, Brazil, Federal University of São Carlos

  • Amando Siuiti Ito

    College of Philosophy, Sciences, and Letters of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil., University of São Paulo

  • Antonio Eduardo da Hora Machado

    Institute of Chemistry, Federal University of Uberlandia, Uberlandia, MG, Brazil.

  • Paulo T Araujo

    Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama, United States, University of Alabama, Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, Alabama 35487, USA

  • Newton M Barbosa Neto

    Graduate Program in Physics, Federal University of Para, Belem, PA, Brazil, Federal University of Pará, Instituto de Ciências Exatas e Naturais – Programa de Pós-graduação em Física, Universidade Federal do Pará, Belém PA 66075-110, Brazil