STUDY OF THE PREDISSOCIATION OF CH3O (A)OVER-TILDE((2)A(1)) BY FAST BEAM PHOTOFRAGMENT TRANSLATIONAL SPECTROSCOPY

The dissociation dynamics of the methoxy radical (CH3O) following exci tation of the (A) over tilde((2)A(1)) <-- (X) over tilde((2)E) transit ion are examined using photofragment translational spectroscopy. The r adicals are produced from photodetachment of a fast, cold negative ion beam. We find that levels of the (A) over tilde, state are strongly p redissociated starting with nu(3), = 6 at 35419 cm(-1) excitation ener gy. Three product channels are identified: (1) CH3 + O, (2) CH2 + OH, and (3) CH3O + H, with channel(1) by far the dominant channel. In chan nel (1), resolved vibrational structure of the methyl fragment is seen in the translational energy distribution, providing insight into the dissociation dynamics of CH3O. Several thermodynamics quantities are a lso obtained: D0(CH3-O) = 87.8 +/- 0.3 kcal/mol, Delta H-f,0(0) (CH3O) = 6.8 +/- 0.4, D0(CH3O-H) = 104.0 +/- 0.5, Delta H-acid,H-0(CH3O-H) = 381.4 +/- 0.7, and D0(H-CH2O)= 19.8 +/- 0.4.