Preresonance Raman Spectrum of the C13H9 Fluorene-like Radical

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2002-08, Vol.106 (30), p.6935-6940
• Main Authors: Szczepanski, Jan, Banisaukas, John, Vala, Martin, Hirata, So, Wiley, William R
• Format: Article
• Language: English
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp020827a

The neutral open-shell species C13H9 formed from fluorene, C13H10, by low-energy electron bombardment and by ultraviolet photolysis in an argon matrix at 12 K has been studied via preresonance Raman, infrared, and ultraviolet/visible spectroscopy. Density functional theory calculations (B3LYP/6-31G(d,p)) of the CH bond energies of neutral fluorene showed that the most probable position for the hydrogen loss is the sp3 carbon in the five-membered ring. Calculations of the C13H9 harmonic vibrational frequencies are shown to match the experimental Raman (and infrared) bands well. A new electronic transition is identified at 283.1 nm (4.38 eV). Its position agrees with earlier time-dependent density functional theory calculations. Oscillator strengths for this transition and three others are estimated. The electronic transitions in the dehydrogenated species, C13H9, are strongly red-shifted compared to fluorene.