Symmetry and Lifetime of the hydroxymethyl radical in the 3p Rydberg state

Hydroxymethyl (CH2OH) radicals were produced in a molecular beam via the ph otoinitiated reaction between Cl atoms and methanol. The rovibronic spectru m obtained following excitation to the 3p Rydberg state was measured by (1 + 1) and (2 + 1) REMPI. Analyses of rotational contours of selected vibroni c bands obtained in the molecular beam and in a flow cell led to the assign ment of the excited Rydberg state as (2)A "(3p(z)). The 11 +/- 2 cm(-1) hom ogeneous linewidth that best fits the observed contours implies a lifetimeo f die excited state of 0.5 + 0.1 ps, consistent with predissociative decay. (C) 2000 Elsevier Science B.V. All rights reserved.