National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA.
Phys Chem Chem Phys. 2018 May 23;20(20):13870-13889. doi: 10.1039/c8cp01102h.
We present a microwave spectral taxonomy study of several hydrocarbon/CS2 discharge mixtures in which more than 60 distinct chemical species, their more abundant isotopic species, and/or their vibrationally excited states were detected using chirped-pulse and cavity Fourier-transform microwave spectroscopies. Taken together, in excess of 85 unique variants were detected, including several new isotopic species and more than 25 new vibrationally excited states of C2S, C3S, and C4S, which have been assigned on the basis of published vibration-rotation interaction constants for C3S, or newly calculated ones for C2S and C4S. On the basis of these precise, low-frequency measurements, several vibrationally exited states of C2S and C3S were subsequently identified in archival millimeter-wave data in the 253-280 GHz frequency range, ultimately providing highly accurate catalogs for astronomical searches. As part of this work, formation pathways of the two smaller carbon-sulfur chains were investigated using 13C isotopic spectroscopy, as was their vibrational excitation. The present study illustrates the utility of microwave spectral taxonomy as a tool for complex mixture analysis, and as a powerful and convenient 'stepping stone' to higher frequency measurements in the millimeter and submillimeter bands.
我们呈现了一项微波光谱分类学研究，该研究涉及几种烃/CS2 放电混合物，其中使用啁啾脉冲和腔傅里叶变换微波光谱学检测到了 60 多种不同的化学物质、它们更丰富的同位素种类、和/或它们的振动激发态。总的来说，检测到了超过 85 种独特的变体，包括几种新的同位素种类和 C2S、C3S 和 C4S 的 25 多个新的振动激发态，这些都是基于 C3S 的已发表的振动-旋转相互作用常数，或者基于 C2S 和 C4S 的新计算值来分配的。基于这些精确的低频测量，随后在 253-280GHz 频率范围内的档案毫米波数据中识别出了 C2S 和 C3S 的几个振动激发态，最终为天文搜索提供了高度准确的目录。作为这项工作的一部分，使用 13C 同位素光谱学研究了这两个较小的碳-硫链的形成途径及其振动激发。本研究说明了微波光谱分类学作为一种复杂混合物分析工具的实用性，以及作为在毫米和亚毫米波段进行更高频率测量的强大而便捷的“垫脚石”的实用性。
