Agenzia Spaziale Italiana, Contrada Terlecchia, 75100 Matera, Italy.
Consiglio Nazionale delle Ricerche-Istituto Nazionale di Ottica, Via Campi Flegrei 34, 80078 Pozzuoli, Italy.
Int J Mol Sci. 2020 Dec 29;22(1):250. doi: 10.3390/ijms22010250.
We review the recent developments in precision ro-vibrational spectroscopy of buffer-gas-cooled neutral molecules, obtained using infrared frequency combs either as direct probe sources or as ultra-accurate optical rulers. In particular, we show how coherent broadband spectroscopy of complex molecules especially benefits from drastic simplification of the spectra brought about by cooling of internal temperatures. Moreover, cooling the translational motion allows longer light-molecule interaction times and hence reduced transit-time broadening effects, crucial for high-precision spectroscopy on simple molecules. In this respect, we report on the progress of absolute frequency metrology experiments with buffer-gas-cooled molecules, focusing on the advanced technologies that led to record measurements with acetylene. Finally, we briefly discuss the prospects for further improving the ultimate accuracy of the spectroscopic frequency measurement.
我们回顾了使用红外频梳作为直接探针源或超精确光学标尺，对缓冲气体冷却中性分子的精密旋转-振动光谱学的最新进展。特别是，我们展示了复杂分子的相干宽带光谱学如何特别受益于内部温度冷却带来的光谱极大简化。此外，冷却平动运动允许更长的光分子相互作用时间，从而减少了对于简单分子的高精度光谱学至关重要的传输时间展宽效应。在这方面，我们报告了使用缓冲气体冷却分子的绝对频率计量实验的进展，重点介绍了导致对乙炔进行创纪录测量的先进技术。最后，我们简要讨论了进一步提高光谱频率测量的最终精度的前景。
