Three-body photodissociation dynamics of (CO2)

The three-body dissociation of I 2 - (CO2) following excitation of the I 2 - chromophore to the repulsive A′2Πg,1/2 and B 2 Σ g , 1 / 2 + electronic states at 1.72 and 3.21 eV has been investigated using fast beam photofragment translational spectroscopy. The translational energy distributions for three-body dissociation provide a direct measurement of the CO2 binding energy, yielding a value of 218 ± 10 meV. These distributions are vibrationally resolved and show that some CO2 is produced with bend excitation. Dalitz plots show that the dominant three-body decay mechanism is asynchronous–concerted decay, in which the two bond cleavages are distinct but nearly simultaneous events.