Optical emission spectroscopy of benzyl radicals produced in a radio-frequency plasma

The benzyl radical was studied by optical emission spectroscopy in gas phase. This radical was produced in a radio-frequency (RF, 13.56 MHz) discharge, using benzyl alcohol (ØCH2OH) as a precursor. The fluorescence from the first excited electronic state 12A2 to ground state 12B2 (450 nm) was studied as a function of several external parameters (pressure, RF power, electrodes and mixtures of the inert gases Ar, Ne, He, N2, with the precursor). We also used a DC discharge to produce this radical but, in this case, the decomposition was fast. We observed changes in the electronic transitions of this radical, and found the best conditions to study it by optogalvanic spectroscopy.