Determination of the branching ratios between vibrational relaxation and reactive removal in collisions of free radicals and other molecules

点击翻译按钮获取中文摘要

A new method for determining the branching ratios between reactive removal and vibrational relaxation has been developed and experimental demonstration has been given. A mixture of OィイD23ィエD2/CHィイD24ィエD2/NィイD22ィエD2 in a flowing cell was photolyzed with a KrF (248nm) laser, and OH(XィイD12ィエD1ΠィイD2iィエD2, 0【less than or equal】υ【less than or equal】4) in the system were detected by laser-induced fluorescence (LIF). Time-dependent profiles of the LIF from the vibrational levels were recorded. The profiles were analyzed using integrated profiles method developed by our lab., and total removal rate constants for all the levels have been determined. The branching ratios between the following vibrational relaxation and reactive removal processes:OH(υ) + CHィイD24ィエD2 → OH(υ-1) + CHィイD24ィエD2 Vibrational relaxation→ Products Reactive removalhave been obtained using reported nascent vibrational distributions of OH in O(ィイD11ィエD1D) + CHィイD24ィエD2 reaction. It has been found that reactive removal process is accelerated with an increase in vibrational energies : k(υ=2)/k(υ=1)/k(υ=0) = 143/33/1.The new method of analysis was also adopted to HCO(υィイD21ィエD2υィイD22ィエD2υィイD23ィエD2) + 0ィイD22ィエD2 reactions. The LIF detection via BィイD4〜ィエD4ィイD12ィエD1A'-XィイD4〜ィエD4ィイD12ィエD1A' transition of HCO was employed to detect HCO. The highly sensitive detection method enabled experiments with parent molecule at very low concentrations. The rate constants for the reactions between HCO((000),(010),(001)) with molecular oxygen have been determined. We have succeeded in what we set out to do according to the plan for the project.