Excitation Spectra of the Jet-Cooled 4-Phenylbenzyl and 4-(4′-Methylphenyl)benzyl Radicals

Abstract

The excitation spectra of jet-cooled 4-phenylbenzyl and 4-(4'-methylphenyl)benzyl radicals have been identified by a combination of resonant two-color two-photon ionization mass spectrometry and quantum chemical methods. Both radicals exhibit progressions in the biphenyl torsional mode, peaking near ν = 17. The lowest observed peak for 4-phenylbenzyl was observed at 18598 cm(-1) and is estimated to be the ν = 3 of the progression, while the lowest observed peak for the 4-(4'-methylphenyl)benzyl radical was observed at 18183 cm(-1) and is possibly the origin. The spectra are discussed and compared to other biphenyl and benzyl chromophores.

VISIBLE ABSORPTIONS OF POTENTIAL DIFFUSE ISM HYDROCARBONS: C9H9 AND C9H5 RADICALS

“…This effect can be even more pronounced in larger entities. Recent laser spectroscopic investigations report many such radicals in supersonic jets (Tsuge et al 2006;Reilly et al 2008Reilly et al , 2009aReilly et al , 2009bTroy et al 2009Troy et al , 2011Troy et al , 2014Sebree et al 2010aSebree et al , 2010bSebree et al , 2011Chalyavi et al 2011Chalyavi et al , 2012Kidwell et al 2013Kidwell et al , 2014O'Connor et al 2013O'Connor et al , 2015Maity et al 2015aMaity et al , 2015b. Several of them could be recognized among the discharge products of the (partly decomposed) 1, 6-heptadiyne precursor, e.g., cis-and trans-1-vinylpropargyl C 5 H 5 (Reilly et al 2009b), 1, 4-pentadienyl C 5 H 7 , benzocyclopropenyl C 7 H 5 (Maity et al 2015b), benzyl C 7 H 7 (Foster & Miller 1989), 1-phenylpropargyl C 9 H 7 (Reilly et al 2009a), and 1-indanyl C 9 H 9 Maity et al 2015a).…”