For more than two decades, encapsulation in superfluid helium nanodroplets has served as a reliable technique for probing the structure and dynamics of molecules and clusters at a low temperature of ≈0.37 K. Due to weak interactions between molecules and the host liquid helium, good spectral resolution can usually be achieved, making helium droplets an ideal matrix for spectroscopy in a wide spectral range from infrared to ultraviolet. Furthermore, rotational structure in the spectra of small molecules provides a unique probe for interactions with the superfluid on an atomic scale. This review presents a summary of results and a discussion of recent experimental developments in helium droplet spectroscopy with the emphasis laid on infrared studies. Initially, studies focused on single molecules and have been expanded to larger species, such as metal-molecular clusters, biomolecules, free radicals, ions, and proteins.

二十多年来，超流氦纳米液滴的封装一直是可靠的技术，可在≈0.37K的低温下探测分子和簇的结构和动力学。由于分子与主体液氦之间的相互作用较弱，因此光谱良好通常可以实现分离度，使氦气液滴成为从红外到紫外线的宽光谱范围内光谱学的理想基质。此外，小分子光谱中的旋转结构为与超流体在原子尺度上相互作用提供了独特的探针。这篇综述介绍了结果的总结，并讨论了氦滴谱研究的最新实验进展，重点是红外研究。最初，研究集中在单个分子上，现已扩展到更大的物种，