TY - JOUR
T1 - The spectroscopy of jet-cooled porphyrins
T2 - An insight into the vibronic structure of the Q band
AU - Beames, Joseph M.
AU - Vaden, Timothy D.
AU - Hudson, Andrew J.
N1 - Funding Information:
AJH is an Engineering and Physical Sciences Research Council (EPSRC) Advanced Research Fellow and TDV was a Royal Society Postdoctoral Fellow at Oxford during this research project. Additional support for this work was provided by the EPSRC and the Central Laser Facility at the Rutherford Appleton Laboratory. Measurements were replicated at the Universities of Bristol and Oxford to corroborate the experimental findings. We thank Prof. John Simons (University of Oxford) for helpful discussions.
PY - 2010/4
Y1 - 2010/4
N2 - We will present resonant two-photon ionization spectra for meso-tetraphenylporphyrin, H 2TPP, measured under isolated conditions. The polycrystalline compound was vaporized, in vacuo, using both thermal and laser desorption, and seeded into a supersonic expansion of an inert-carrier gas. The molecules remain largely intact in the gaseous phase. However, the two techniques for vaporizing H 2TPP give different internal temperatures for the isolated substrate, with greater vibrational cooling achieved using laser desorption. A comparison of the peak positions and intensities in the resonant two-photon ionization spectra of thermal- and laser-desorbed molecules provides an insight into the vibrational structure of the Q band. In particular, the greater contribution made by electronic transitions originating from higher vibrational levels in the ground state of H 2TPP is emphasized. We conclude that vibronic coupling in the ground electronic state plays an important role in a quantum-mechanical interpretation of the Q band.
AB - We will present resonant two-photon ionization spectra for meso-tetraphenylporphyrin, H 2TPP, measured under isolated conditions. The polycrystalline compound was vaporized, in vacuo, using both thermal and laser desorption, and seeded into a supersonic expansion of an inert-carrier gas. The molecules remain largely intact in the gaseous phase. However, the two techniques for vaporizing H 2TPP give different internal temperatures for the isolated substrate, with greater vibrational cooling achieved using laser desorption. A comparison of the peak positions and intensities in the resonant two-photon ionization spectra of thermal- and laser-desorbed molecules provides an insight into the vibrational structure of the Q band. In particular, the greater contribution made by electronic transitions originating from higher vibrational levels in the ground state of H 2TPP is emphasized. We conclude that vibronic coupling in the ground electronic state plays an important role in a quantum-mechanical interpretation of the Q band.
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U2 - 10.1142/S1088424610002094
DO - 10.1142/S1088424610002094
M3 - Article
AN - SCOPUS:77953863126
SN - 1088-4246
VL - 14
SP - 314
EP - 323
JO - Journal of Porphyrins and Phthalocyanines
JF - Journal of Porphyrins and Phthalocyanines
IS - 4
ER -