Alkali halide photofragment spectra. III. Alkali chloride bond energies and excited state symmetries at 266 nm

Photofragment spectroscopy studies of the four heavier alkali chlorides at 266 nm are reported. Alkali atom recoil time-of-flight distributions provide indirect evidence for production of both ground 2P3/2 and excited 2P1/2 Cl atoms, but quantitative branching ratios are only approximate. The following bond dissociation energies (D00, kcal mole−1, all uncertainties ±2 kcal mole−1) are determined: NaCl=97.6; KCl=102.6; RbCl=101.3; CsCl=104.4. From recoil angular distributions the percentage parallel transition intensities to the unresolved excited states are calculated to be: NaCl=16±2; KCl=26±5; RbCl=32±1; CsCl=25±6.