Photodissociation dynamics of ClO radicals at 248 nm
- Lawrence Berkeley Lab., CA (United States)
The photodissociation of ClO radicals produced photolytically in a molecular beam was studied at 248 nm using photofragment translational energy spectroscopy. Excitation into the ClO absorption continuum to the blue of the structured region of the ClO(A{sup 2}{Pi} IMP X{sup 2}{Pi}) spectrum led to dominant (nearly 97%) formation of Cl({sup 2}P{sub 3/2}) + O({sup 1}D{sub 2}) with negligible (< 0.5%) production of Cl{sup 2}P{sub 1/2} + O({sup 1}D{sub 2}). The photofragment anisotropy parameter ({beta}) was measured to be 1.2 {+-} 0.2 for the dominant Cl({sup 2}P{sub 3/2}) + O({sup 1}D{sub 2}) channel, significantly less than the limiting value of 2.0 expected for the parallel ClO (A{sup 2}{Pi} IMP X{sup 2}{Pi}) transition. This indicates that, in the ClO continuum region near 248 nm, absorption to an as yet uncharacterized electronic state [probably B({sup 2}{Sigma}{sup +})] carries nearly 30% of the oscillator strength. This state, like ClO(A{sup 2}{Pi}), dissociates primarily to CL({sup 2}P{sub 3/2}) + O({sup 1}D{sub 2}). A second minor photodissociation channel, accounting for approximately 3% of the ClO absorption cross section, leads to production of Cl{sup 2}P{sub {1/2}} + O({sup 3}P{sub J}). As in the photodissociation of ClO below the A{sup 2}{Pi} convergence limit, this minor channel probably involves predissociation of ClO(A{sup 2}{Pi}) by one or more as yet uncharacterized repulsive electronic surfaces. 41 refs., 8 figs., 1 tab.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 196630
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 1 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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