IRFEL Selective Irradiation of Amorphous Solid Water: from Dangling to Bulk Modes
IRFEL Selective Irradiation of Amorphous Solid Water: from Dangling to Bulk Modes
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DOI：
10.1021/acs.jpca.2c00054
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发表时间：
2022-04-14
影响因子：
2.9
通讯作者：
Ioppolo, Sergio
中科院分区：
文献类型：
--
作者：
Coussan, Stephane;Noble, Jennifer A.;Ioppolo, Sergio
非晶固体水（ASW）是研究最广泛的固相体系之一。然而，更好地理解ASW中分子间和分子内力的性质，仍然需要正确解释ASW在环境中形成和保存分子物种的催化作用，例如太阳系物体的冰表面，星际冰尘颗粒，甚至可能在地球大气层的上层。在这项工作中，我们系统地将多孔asw （pASW）暴露在荷兰HFML-FELIX设施的自由电子激光器产生的中红外辐射下，研究了振动能量注入到pASW表面和体模的影响。在对同一冰点进行多次连续照射时，我们观察到冰面和冰体的选择性效应。虽然pASW中的态密度应该允许通过h键网络快速振动松弛，但在反射-吸收模式下进行傅里叶变换红外光谱时观察到的光谱变化表明，部分注入能量被转换为结构冰的变化。未来的研究将包括通过系统地调查冰的厚度、冰的形态和冰的组成来量化这种影响
Amorphous solid water (ASW) is one of the mostwidely studied solid phase systems. A better understanding of thenature of inter- and intramolecular forces in ASW is, however, stillrequired to correctly interpret the catalytic role of ASW in theformation and preservation of molecular species in environmentssuch as the icy surfaces of Solar System objects, on interstellar icydust grains, and potentially even in the upper layers of the Earth'satmosphere. In this work, we have systematically exposed porousASW (pASW) to mid-infrared radiation generated by a free-electronlaser at the HFML-FELIX facility in The Netherlands to study theeffect of vibrational energy injection into the surface and bulk modesof pASW. During multiple sequential irradiations on the same icespot, we observed selective effects both at the surface and in the bulkof the ice. Although the density of states in pASW should allow for afast vibrational relaxation through the H-bonded network, part of the injected energy is converted into structural ice changes asillustrated by the observation of spectral modifications when performing Fourier transform infrared spectroscopy in reflection-absorption mode. Future studies will include the quantification of such effects by systematically investigating ice thickness, icemorphology, and ice composition