论文标题
在液态违反的紫外线光解过程中，直接观察和定量测量OH自由基解吸
Direct Observation and Quantitative Measurement of OH Radical Desorption During the Ultraviolet Photolysis of Liquid Nonanoic Acid
论文作者
论文摘要
最近有人建议在对流层中羟基酸（NA）等海洋中发现脂肪酸表面活性剂的紫外线（紫外）光解，这些脂肪酸表面活性剂覆盖了大气液气溶胶的表面，并在海洋中被发现为羟基酸（NA）。我们使用激光诱导的荧光直接观察从纯液体Na表面解脱为213 nm辐照后的主要光产物。 OH自由基解吸的光反应横截面的上限估计为9.0（4.1）$ \ times $ 10 $^{ - 22} $ cm $^2 $，仅为1.2 $ \ pm $ \ pm $ 0.8％的光电横截面的0.8％，该光电横截面是用于对加油剂乙酸单位的光解。液体NA的振动总和频产生光谱揭示了Na分子在液体表面的氢键，环状的二聚体结构。这种二聚化可以抑制OH自由基的形成，并导致液体NA的当前低光化学反应性。
Ultraviolet (UV) photolysis of fatty acid surfactants which cover the surfaces of atmospheric liquid aerosols and are found in the oceans such as nonanoic acid (NA) has recently been suggested as a source of hydroxyl (OH) radicals in the troposphere. We used laser-induced fluorescence to directly observe OH radicals desorbed from the surface of neat liquid NA as a primary photoproduct following 213 nm irradiation. The upper limit of photoreaction cross section for the OH radical desorption was estimated to be 9.0(4.1) $\times$ 10$^{-22}$ cm$^2$, which is only 1.2$\pm$0.8% of the photoreaction cross section established for the photolysis of gas-phase acetic acid monomers. Vibrational sum-frequency generation spectroscopy for liquid NA revealed the hydrogen-bonded, cyclic, dimer structure of the NA molecules at the liquid surface. This dimerization can inhibit the formation of OH radicals and lead the present low photochemical reactivity of liquid NA.
