Molecular ions have long been considered key intermediates in the evolution of molecular complexity in the interstellar medium. However, owing to their reactivity and transient nature, ions have historically proved challenging to study in terrestrial laboratory experiments. In turn, their detection and characterization in space is often contingent upon advances in the laboratory spectroscopic techniques used to measure their spectra. In this Review, we discuss the advances over the past 50 years in laboratory methodologies for producing molecular ions and probing their rotational, vibrational and electronic spectra. We largely focus this discussion around the widespread H₃⁺ cation and the ionic products originating from its reaction with carbon atoms. Finally, we discuss the current frontiers in this research and the technical advances required to address the spectroscopic challenges that they represent.

长期以来，分子离子一直被认为是星际介质中分子复杂性演变的关键中间体。但是，由于离子的反应性和瞬态性质，从历史上看，离子很难在地面实验室实验中进行研究。反过来，它们在空间中的检测和表征通常取决于用于测量其光谱的实验室光谱技术的发展。在这篇综述中，我们讨论了过去50年中实验室方法在产生分子离子并探测其旋转，振动和电子光谱方面的进展。我们主要围绕广泛的H ₃ ⁺进行讨论。阳离子及其源自碳原子反应的离子产物。最后，我们讨论了这项研究的当前前沿以及解决它们所代表的光谱挑战所需的技术进步。