Isotopically selective dissociation of CCl4 molecules by highpower NH3 laser radiation

Isotopically selective many-photon dissociation of the CCl₄ molecules was achieved for the first time in the field of radiation emitted from an NH₃ molecular laser pumped optically by a CO₂ laser. The dependence of the dissociation rate on the initial pressure of CCl₄ was unusual: the rate first fell on increase of the pressure (as in all other known cases) and then it rose. The ratio of the dissociation rates of ¹²CCl₄ and ¹³CCl₄ was 4.4 ± 0.3. Two-frequency excitation by the weak resonant field of the NH₃ laser and dissociation by the strong nonresonant field of the CO₂ laser (λ_l = 9.29 μ) was achieved. The detuning on the violet side was 300 cm^–1, which was considerably greater than in the published experiments on the dissociation of SF₆ by CO₂ laser radiation.