Direct detection of polar structure formation in helium nanodroplets by beam deflection measurements
Direct detection of polar structure formation in helium nanodroplets by beam deflection measurements
复制标题
通过光束偏转测量直接检测氦纳米液滴中极性结构的形成
DOI：
10.1039/c9cp04322e
复制
发表时间：
2019
影响因子：
3.3
通讯作者：
Kresin, Vitaly V.
中科院分区：
文献类型：
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作者：
Niman, John W.;Kamerin, Benjamin S.;Kranabetter, Lorenz;Merthe, Daniel J.;Suchan, Jiří;Slavíček, Petr;Kresin, Vitaly V.
长程分子间力能够将浸没在超流氦纳米液滴中的极性分子引导成高度极性的亚稳态构型。我们证明，这种特殊结构的存在下，可以识别，在一个直接和确定的方式，通过静电偏转的掺杂纳米液滴束。测量还确定了结构的电偶极矩。因此，介绍的方法是补充低温分子组装反应的光谱研究。这是由于在冷的超流基质中，分子偶极子几乎完全被施加的电场定向。结果，大量的（数万个氦原子）纳米液滴发生了显著的偏转。该方法在这里示出的二甲基亚砜（DMSO）分子的二聚体和三聚体的应用程序。我们用从头算理论解释了实验结果，绘制了DMSO配合物的势能面，模拟了它们的低温聚集动力学。
Long-range intermolecular forces are able to steer polar molecules submerged in superfluid helium nanodroplets into highly polar metastable configurations. We demonstrate that the presence of such special structures can be identified, in a direct and determinative way, by electrostatic deflection of the doped nanodroplet beam. The measurement also establishes the structures’ electric dipole moments. In consequence, the introduced approach is complementary to spectroscopic studies of low-temperature molecular assembly reactions. It is enabled by the fact that within the cold superfluid matrix the molecular dipoles become nearly completely oriented by the applied electric field. As a result, the massive (tens of thousands of helium atoms) nanodroplets undergo significant deflections. The method is illustrated here by an application to dimers and trimers of dimethyl sulfoxide (DMSO) molecules. We interpret the experimental results with ab initio theory, mapping the potential energy surface of DMSO complexes and simulating their low temperature aggregation dynamics.