Using a combination of photostimulated desorption and resonance-enhanced multiphoton ionization techniques, OH radicals photodesorbed from amorphous solid water at low temperatures are detected. It was found that the OH photodesorption can be caused by a one-photon process on the surface even at 532 nm, where both isolated OH and ${\mathrm{H}}_2\mathrm{O}$ are transparent. Quantum chemical calculations reveal that the electronic excitation of OH dramatically changes depending on the adsorption sites and the number of surrounding ${\mathrm{H}}_2\mathrm{O}$ molecules, and that OH having three hydrogen bonds with neighboring ${\mathrm{H}}_2\mathrm{O}$ molecules can absorb photons of around 532 nm, which supports the experimental findings.

中文翻译：

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从无定形固体水中光解OH自由基：可见光与OH-冰络合物相互作用的证据

结合使用光刺激解吸和共振增强多光子电离技术，可以检测到在低温下从无定形固体水中光解吸的OH自由基。发现OH的光解吸可能是由于表面上的单光子过程引起的，即使在532 nm处，分离的OH和${\mathrm{H}}_2\mathrm{Ø}$是透明的。量子化学计算表明，OH的电子激发根据吸附位点和周围的数目而发生显着变化${\mathrm{H}}_2\mathrm{Ø}$ 分子，以及与相邻氢原子具有三个氢键的OH ${\mathrm{H}}_2\mathrm{Ø}$ 分子可以吸收约532 nm的光子，这支持了实验结果。