Cavity ring-down spectroscopy and vibronic activity of benzo[ghi]perylene
1Space Science Division, National Aeronautics and Space Administration (NASA) Ames Research Center, Mail Stop 245-6, Moffett Field, California 94035-1000, USA. x.tan@jhu.edu
Abstract:
Gas-phase cavity ring-down spectroscopy of jet-cooled benzo[ghi]perylene (C22H12) in the 26 950-28 600-cm(-1) spectral range is reported for the first time. This study is part of our extensive laboratory astrophysics program for the study of interstellar polycyclic aromatic hydrocarbons. The observed spectrum shows an intermediate level structure and significant broadening and is associated with the vibronically coupled S1(1A1)<--S0(1A1) and S2(1B1)<--S0(1A1) electronic transitions. Time-dependent density-functional calculations were performed to calculate the energetics, vibrational frequencies, and normal coordinates of the S1 and S2 states. A simple vibronic model was employed to account for the vibronic interaction between the vibronic levels of the S1 and S2 states. The calculated vibronic spectrum is found to be in good agreement with the experimental spectrum.
More Related Videos
Related Concept Videos
Structure of Benzene: Molecular Orbital Model
Frost Circles for Different Conjugated Systems
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group with both...
NMR Spectroscopy of Aromatic Compounds
NMR Spectroscopy of Benzene Derivatives
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds


