Translational spectroscopy studies of the photodissociation dynamics of O−4

Abstract

An investigation of the photodissociation dynamics of the dimer anion O 4 Ϫ at 523.6, 349.0, and 261.8 nm is reported. Product translational energy and angular distributions have been obtained using photofragment translational spectroscopy in a fast ion beam. At all wavelengths photodissociation ͑O 4 Ϫ ϩh→O 2 ϩO 2 Ϫ ͒ is observed to proceed via a rapid parallel electronic transition, with the photofragment angular distribution strongly peaked along the laser electric vector. The lowest energy photodissociation channel produces O 2 (a 1 ⌬ g) and ground state O 2 Ϫ (X 2 ⌸ g), indicating that O 4 Ϫ is a doublet anion. The partitioning of energy in the dissociation reveals a complicated wavelength dependence.

Photochemistry of Ions at D-region Altitudes of the Ionosphere: A Review

“…The resulting value of K 1 dis is calculated to be 0.072 s -1 . A series of experiments (Hanold et al 1995Sherwood et al 1996;Li et al 1997a;Khuseynov et al 2012) designed to clarify the photochemistry of O 4 -have shown that this ion undergoes two photodestruction processes in the wavelength range from 262 to 532 nm: photodissociation (reaction 10 of Table 12) and dissociative photodetachment (reaction 11 of Table 12). As a result of these studies, the O 4 -?hm ?…”

Temperature dependence of the oxide ion/ozone reaction in the gas phase

“…The trans O 4 − planar structure that should be more easily formed from O 3 − + O, is only slightly higher in energy (∼37 kJ/mol) [20,21] and is expected to readily interconvert with the rectangular structure [20]. Sherwood et al [22,23] In this mechanism, the change in branching fraction with increasing temperature arises from a decrease in the lifetime of the charge transfer complex with increasing temperature; the charge transfer products separate before the atom/ion transfer can take place. The large fraction of collisions that form charge transfer products regardless of temperature (∼2/3 over our temperature range) may not be involved in this long-lived complex but rather may proceed by a direct or long-range charge transfer mechanism.…”

Dissociative Photodetachment Studies of Transient Molecules by Coincidence Techniques

“…The error bars are determined by taking the errors in eKE and ET in quadrature, along with a 20-meV allowance for the precision of the ET measurement. 69 If it is assumed that this rotational energy is shared equally between the two diatom products, a peak value of J 14, corresponding to 40 meV in rotation of each 02, is predicted. The narrow product rotational distribution inferred from the sharp vibrational features implies that dissociation of 04 occurs from a structure with a small exit-channel impact parameter.…”