The spectra of the (X) over tilde (2)A'-(A) over tilde (2)A" electronic tra
nsition of jet-cooled vinyl radical, C2H3, and its partially deuterated iso
topomer, CD2CH, have been obtained via action spectroscopy. The appearance
of the H or D fragment was monitored via 1+1' resonance enhanced multiphoto
n ionization through the Lyman-alpha transition. The vibrational structure
of the (A) over tilde (2)A" state was fully resolved and analyzed. The expe
rimental vibrational frequencies agree well with ab initio calculations. Th
e simulation of the rotational structure of several bands reinforces vibrat
ional assignments. (C) 2001 American Institute of Physics.