Abstract In this paper, we measured the absolute line intensities and air broadening coefficients of several rotationally resolved lines in the P and R branches of the allowed (ν4 + ν5)0 and forbidden (ν4 + ν5)2 vibrational combinational bands of C2H2 at room temperature 296 K. These measurements were performed using an external-cavity quantum cascade laser (EC-QCL) operating at 7.5 μm coupled with high-sensitive cavity ring-down spectroscopy (CRDS). Rotational level-dependent pressure-broadening coefficients of the resolved spectral lines of the selected transitions from (ν4 + ν5)0 band are reported here. The air broadening coefficients for 5 rotational lines from P-branch of (ν4 + ν5)2 band were also obtained first time with better than 3% uncertainty. The vibrational transition dipole moment squared values of the rotational lines and empirical Herman-Wallis coefficients were also quantified from experimental data. Finally, experimentally obtained all spectroscopic parameters were rigorously compared with previous studies. The new experimental data including several spectroscopic parameters will be useful for atmospheric and astrophysics applications.

中文翻译：

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使用外腔量子级联激光器对 C2H2 的允许 (ν4+ν5)0 和禁止 (ν4+ν5)2 波段进行高分辨率连续腔衰荡光谱

摘要 在本文中，我们测量了室温下 C2H2 的允许 (ν4 + ν5)0 和禁止 (ν4 + ν5)2 振动组合带的 P 和 R 分支中几条旋转分辨线的绝对线强度和空气展宽系数。温度为 296 K。这些测量是使用工作在 7.5 μm 的外腔量子级联激光器 (EC-QCL) 和高灵敏度腔衰荡光谱 (CRDS) 进行的。此处报告了来自 (ν4 + ν5)0 波段的所选跃迁的解析谱线的旋转水平相关压力展宽系数。还首次获得了来自 (ν4 + ν5)2 波段 P 分支的 5 条旋转线的空气展宽系数，其不确定性优于 3%。旋转线的振动跃迁偶极矩平方值和经验 Herman-Wallis 系数也从实验数据中量化。最后，通过实验获得的所有光谱参数与之前的研究进行了严格的比较。包括几个光谱参数在内的新实验数据将有助于大气和天体物理学应用。