The disposal of excess energy above the dissociation threshold into internal excitation and translation in a photochemical decomposition of C2N2has been determined by utilizing a technique by which measurements of the recoil velocity distribution for particular rotational states are possible. Simple phase space theory calculations appear to give a fairly good interpretation of the rotational energy distributions in a particular vibrational state, while the vibrational energy disposal is definitely nonstatistical with only about 63percnt; of the total population predicted by statistical calculation in the first vibrational state and no excitation observed in thev=2 state. Our experimental results support the previous predictions of high translational energy disposal (thinsp;fT=75percnt;) compared to a low or moderate product internal state excitations (thinsp;fR=18.6percnt;,fv=6.4percnt;). We also measure the dissociation energy of C2N2to be 133plusmn;1 kcal/mol rather than the previously reported 128plusmn;1 kcal/mol.
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