Toennies J Peter, Vilesov Andrey F
Max Planck Iinstitute for Fluid Dynamics (Strömungsforschung), Göttingen, Germany.
Angew Chem Int Ed Engl. 2004 May 10;43(20):2622-48. doi: 10.1002/anie.200300611.
Herein, recent experiments on the spectroscopy and chemical reactions of molecules and complexes embedded in helium droplets are reviewed. In the droplets, a high spectroscopic resolution, which is comparable to the gas phase is achieved, while an isothermal low-temperature environment is maintained by evaporative cooling at T =0.37 K (4He droplets) or 0.15 K (3He droplets), lower than possible in most solid matrices. Thus the helium-droplet technique combines the benefits of both the gas phase and the classical matrix-isolation techniques. Most important, the superfluid helium facilitates binary encounters, and absorbs the released binding energy upon recombination. Thus the droplet can be viewed as an isothermal nanoscopic reactor, which isolates single molecules, clusters, or even a single reactive encounter at ultralow temperatures.
本文综述了近期关于嵌入氦滴中的分子和配合物的光谱学及化学反应的实验。在这些液滴中，能实现与气相相当的高光谱分辨率，同时通过在T = 0.37 K（4He液滴）或0.15 K（3He液滴）下的蒸发冷却维持等温低温环境，这一温度低于大多数固体基质所能达到的温度。因此，氦滴技术结合了气相和经典基质隔离技术的优点。最重要的是，超流氦促进二元碰撞，并在重组时吸收释放的结合能。因此，液滴可被视为一个等温纳米反应器，它能在超低温下隔离单个分子、团簇，甚至单个反应碰撞。
