Primary and secondary dissociation pathways in the ultraviolet photolysis of Cl2O

Abstract

The photodissociation of dichlorine monoxide (Cl,O) at 308, 248, and 193 nm was studied by photofragment translational energy spectroscopy. The primary channel upon excitation at 308 and 248 nm was Cl-O bond fission with production of ClO+Cl. A fraction of the Cl0 photoproducts also underwent spontaneous secondary dissociation at 248 nm. The center-of-mass translational energy distribution for the ClO+C!l channel at 248 nm appeared to be bimodal with a high energy component that was similar in shape to the 308 mn distribution and a second, low energy component with a maximum close to the threshold for the 2Cl+O(3P) channel. Observation of a bimodal distribution suggests that two pathways with different dissociation dynamics lead to CIO+Cl products. The high product internal energy of the second component raises the possibility that Cl0 is formed in a previously unobserved spin-excited state a 4Z-. Following excitation at 193 nm, a concerted dissociation pathway leading to Cl,+0 was observed in addition to primary Cl-O bond breakage. In both processes, most of the diatomic photofragments were formed with sufficient internal energy that they spontaneously dissociated. The time-of-flight distributions of the Cl,+0 products suggest that these fragments are formed in two different channels Cl,(311)+O(3P) and Cl,(X 'Iz)+-@I).-

Environmental effects of large igneous province magmatism: a Siberian perspective

“…Plane and Husain [1060] reported that ~0.01 of the Na product is in the 3 2 P excited state, while Griffin et al [527] report a Na 3 2 P product branching ratio of 0.14±0.04. This difference is consistent with the orbital correlation predictions of products for reaction of each NaO state as presented by Herschbach et al [578]. (Table: 06-2, Note: 06-2) Back to Table J5.…”

“…The main photolysis products are Cl and ClO. Using a molecular beam technique, Nelson et al [578] found Cl + ClO to be the only primary photodissociation channel at 308 nm, a major channel at 248 nm, and a minor channel at 193 nm. At 248 nm a fraction of the photoproduct ClO underwent spontaneous photodissociation.…”

Photodissociation of Cl2O at 248 and 308 nm

“…As we reported in a previous publication, 1 the formation of ClϩClO products ͑ ⌬H 0 o ϭ33.8 kcal/mol͒ 2 is the only channel observed for Cl 2 O photolysis at 308 nm and is the major channel at 248 nm. We have repeated the Cl 2 O photolysis experiment at 248 and 308 nm and present here a refinement of the analysis for the ClϩClO channel.…”

Rate coefficient for the reaction: Br+Br2O?Br2+BrO

“…Nelson et al [14] have studied the photolysis of the analogous chlorine compound, Cl 2 O, at 193, 248, and 308 nm. They used the technique of photofragment translational energy spectroscopy to identify the various photolysis channels.…”