Rotational contour analysis of the electronic origin band in the emission spectrum of the orthoxylyl radical at 4683 angstrom

The rotational contour of the 4683 angstrom emission band of the o-xylyl radical was studied at high resolution. Calculations of the rotational contour of this hybrid band Were Made in the rigid rotor approximation for various sets of values of the excited state rotational constants and directions of the transition Moment A. Matching of computed and experimental rotational features showed that Is is oriented at +37 degrees or similar to 37 degrees with respect to the b inertial axis. The nature of the excited states of o-xylyl and the methyl-to-ring interaction are discussed with respect to these two possible assignments.