PHOTOLYSIS OF MATRIX-ISOLATED HCL-CL-2 COMPLEXES - ELECTRONIC ABSORPTION AND EMISSION-SPECTRA PROVISIONALLY ASSIGNED TO CL-3

A new visible emission system, tentatively assigned to the trichloride radical, has been observed in a solid Ar matrix. Cl-3 was prepared by photodissociation of HCl and permanent cage exit of the H atom from H Cl/Cl-2 dimer trapping sites. Following photodissociation at 193 nm, l aser excitation and wavelength-resolved fluorescence measurements were used to examine the photoproducts. Excitation at 308 nm produced a br oad emission centered at 470 nm. This band was emitted with a lifetime of 44 +/- 2 mu s. An excitation spectrum, recorded by monitoring the 470 nm emission, exhibited a single broad peak centered at 312 nm, The emission spectrum and lifetime were in agreement with gas phase resul ts that were previously attributed to Cl-3 [Kawasaki et al. J. Phys. C hem. 1989, 93, 7571]. The excitation spectrum correlates with the 320 nm absorption band of the isoelectronic F2Cl radical [Prochaska and An drews, J. Inorg. Chem. 1977, 16, 339]. Additional elements of circumst antial evidence that support assignment of the matrix observations to Cl-3 are presented.