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

Abstract

The photodissociation dynamics of I 3 Ϫ from 390 to 290 nm ͑3.18 to 4.28 eV͒ have been investigated using fast beam photofragment translational spectroscopy in which the products are detected and analyzed with coincidence imaging. At photon energies р3.87 eV, two-body dissociation that generates I Ϫ ϩI 2 (A 3 ⌸ 1u ) and vibrationally excited I 2 Ϫ (X 2 ⌺ u ϩ )ϩI( 2 P 3/2 ) is observed, while at energies у3.87 eV, I*( 2 P 1/2 )ϩI 2 Ϫ (X 2 ⌺ u ϩ ) is the primary two-body dissociation channel. In addition, three-body dissociation yielding I Ϫ ϩ2I( 2 P 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.

Two- and three-body photodissociation dynamics of diiodobromide (I2Br−) anion

“…These translational energy distributions are similar to those from the lower absorption band of I − 3 , where the two-body channels blended seamlessly into the corresponding three-body channels, 14 and suggest that two-and three-body dissociation occur via the same dynamical process. Specifically, at 4.13 eV, the Br( 2 P 3/2 ) + I − 2 (X 2 + u ) and I − ( 1 S) + IBr channels (1B, 2A, 2B, and 2C) all correlate to channel 3B in the limit of maximum internal excitation of the diatomic fragment, and the two-body P(E T ) distributions all feature sharp falloffs at E min T .…”

“…It is interesting that no evidence for similar sequential three-body dissociation has been observed in I − 3 , either in our group 13,14 or others. 15,16 While we only tentatively assigned an I − ( 1 S) + I 2 (B 3 + 0u ) product channel, Nakanishi 15 assigned the channel at nearly the same photon energy (4.28 and 4.27 eV, respectively) with a branching fraction of 0.11.…”

“…[8][9][10] Gas phase experiments have also characterized the energetics 11,12 and primary photochemistry of I − 3 with emphasis on elucidating the branching ratios among the available two-and three-body product channels. [13][14][15][16] In this paper, the photodissociation dynamics of I 2 Br − , which is isovalent to I − 3 but noncentrosymmetric, are investigated with the goal of understanding how the two-and three-body dissociation dynamics of a trihalide change when its symmetry is broken.…”

Three-Body Breakup in the Dissociative Recombination of the Covalent Triatomic Molecular IonO3+

“…Geppert et al reported evidence for a four-body breakup in the DR of C 2 D 5 [18], though this was not the dominant channel. It is noted that multiple fragmentation has also been seen in several different types of reaction processes [19][20][21] and is not exclusive to DR.…”

Coherent ultrafast lattice-directed reaction dynamics of triiodide anion photodissociation

“…Even within this relatively small system, there is a wealth of interactions that probe nearly all aspects of the SBI. The I 3 − anion dissociates into various iodine-containing fragments 7,8 upon photoexcitation to either of its two major absorption bands (labelled C and D in Fig. 1b).…”