Two- and three-body photodissociation of gas phase I3-

The photodissociation dynamics of I-3(-) from 390 to 290 nm (3.18 to 4.28 eV) have been investigated using fast beam photofragment translational spectroscopy in which the products are detected and analyzed with coincidence imaging. At photon energies less than or equal to3.87 eV, two-body dissociation that generates I- + I-2 (A (3)Pi(1u)) and vibrationally excited I-2(-) (X(2)Sigma(u)(+))+I(P-2(3/2)) is observed, while at energies greater than or equal to3.87 eV, I*(P-2(1/2)) +I-2(-) (X(2)Sigma(u)(+)) is the primary two-body dissociation channel. In addition, three-body dissociation yielding I- + 2 I(P-2(3/2)) photofragments is seen throughout the energy range probed; this is the dominant channel at all but the lowest photon energy. Analysis of the three-body dissociation events indicates that this channel results primarily from a synchronous concerted decay mechanism. (C) 2004 American Institute of Physics.