Rotational spectroscopy as a tool to investigate interactions between vibrational polyads in symmetric top molecules: low-lying states $v_8 \le 2$ of methyl cyanide, CH$_3$CN
Holger S. P. Müller, Linda R. Brown, Brian J. Drouin, John C. Pearson, Isabelle Kleiner, Robert L. Sams, Keeyoon Sung, Matthias H. Ordu, Frank Lewen
备注：
20 pages, astract abbreviated; appeared in Journal of Molecular Spectroscopy; CDMS links updated; dipole values in Table 10 corrected (were correct in text)
Spectra of methyl cyanide were recorded to analyze interactions in low-lying vibrational states and to construct line lists for radio astronomical observations as well as for infrared spectroscopic investigations of planetary atmospheres. The rotational spectra cover large portions of the 36$-$1627 GHz region. In the infrared (IR), a spectrum was recorded for this study in the region of 2$ν_8$ around 717 cm$^{-1}$ with assignments covering 684$-$765 cm$^{-1}$. Additional spectra in the $ν_8$ region were used to validate the analysis.
The large amount and the high accuracy of the rotational data extend to much higher $J$ and $K$ quantum numbers and allowed us to investigate for the first time in depth local interactions between these states which occur at high $K$ values. In particular, we have detected several interactions between $v_8 = 1$ and 2. Notably, there is a strong $Δv_8 = \pm1$, $ΔK = 0$, $Δl = \pm3$ Fermi resonance between $v_8 = 1^{-1}$ and $v_8 = 2^{+2}$ at $K$ = 14. Pronounced effects in the spectrum are also caused by resonant $Δv_8 = \pm1$, $ΔK = \mp2$, $Δl = \pm1$ interactions between $v_8 = 1$ and 2. An equivalent resonant interaction occurs between $K$ = 14 of the ground vibrational state and $K$ = 12, $l = +1$ of $v_8 = 1$ for which we present the first detailed account. A preliminary account was given in an earlier study on the ground vibrational state. From data pertaining to $v_8 = 2$, we also investigated rotational interactions with $v_4 = 1$ as well as $Δv_8 = \pm1$, $ΔK = 0$, $Δl = \pm3$ Fermi interactions between $v_8 = 2$ and 3.
We have derived N$_2$- and self-broadening coefficients for the $ν_8$, 2$ν_8 - ν_8$, and 2$ν_8$ bands from previously determined nu4 values. Subsequently, we determined transition moments and intensities for the three IR bands.
Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) -- IV. Methyl cyanide isotopologues toward BHR71-IRS1
European Southern Observatory（欧洲南方天文台）；Institut de Recherche en Astrophysique et Planétologie（天体物理与行星学研究所）；Université de Toulouse（图卢兹大学）；CNRS（法国国家科学研究中心）；CNES（法国国家空间研究中心）；Niels Bohr Institute（尼尔斯·玻尔研究所）；University of Copenhagen（哥本哈根大学）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文学研究所）；National Radio Astronomy Observatory（美国国家射电天文台）；Univ. Grenoble Alpes（格勒诺布尔阿尔卑斯大学）；IPAG（格勒诺布尔天体物理与行星学研究所）；National Tsinghua University（国立清华大学）；Physikalisch-Meteorologisches Observatorium Davos und Weltstrahlungszentrum (PMOD/WRC)（达沃斯物理气象观测站暨世界辐射中心）；Universität Bern（伯尔尼大学）；Seoul National University（首尔国立大学）
Toward a global model of the interactions in low-lying states of methyl cyanide: rotational and rovibrational spectroscopy of the $v_4 = 1$ state and tentative interstellar detection of the $v_4 = v_8 = 1$ state in Sgr B2(N)
通过对新的和已有的乙腈分子转动光谱的分析，将低振动态及其相互作用的整体模型推广到$v_4=1$（920 cm $^{-1}$）.旋转光谱覆盖了36 $-$ 1439 GHz区域的大部分，并分别达到量子数$J$和$K$为79和16。CH $_3$ CN的$K$能级结构的信息由IR光谱获得。在我们以前的研究中分析的717 cm $^{-1}$周围的$2ν_8$光谱也覆盖了$ν_4$带。在这个波段的分配覆盖880 $-$ 952 cm $^{-1}$，获得的量子数$J$和$K$分别为61和13。$v_4=1$最重要的相互作用似乎是与$v_8=3$、$ΔK=0$、$Δl=+3$的相互作用，这是一种先前表征的非谐共振。我们报告了与$ΔK=-2$和$Δl=+1$，与$ΔK=-4$和$Δl=-1$，与$ΔK=-6$和$Δl=-3$相互作用的新分析;这四种类型的相互作用将$v_8=3$的所有$l$亚态能量连接到$v_4=1$。还分析了已知的$ΔK=-2$、$Δl=+1$与$v_7=1$的相互作用，并且改进了对$ΔK=+1$、$Δl=-2$和$ΔK=+3$、$Δl=0$与$v_8=2$的共振的研究，以及主要通过新的$v_8\le 2$旋转数据改进了连续状态与$v_8\le 3$之间的相互作用。基于转动跃迁频率和$ν_4+ν_8-ν_8$热带数据对$v_4=v_8=1$态进行了初步的单态分析。尽管$v…
Digging into the Massive Protostar S255IR NIRS3: A Study of Nitrogen-Bearing Molecules and Their Prebiotic Chemistry
S. N. Bose National Centre for Basic Sciences（S.N. 玻色基础科学国家中心）；Midnapore City College（金奈浦城市学院）；Dinabandhu Andrews Institute of Technology and Management（迪南德胡·安德鲁斯技术与管理学院）；Sidho Kanho Birsha University（西多·坎霍·比尔沙大学）
Rotational Spectroscopy as a Tool to Study Vibration-Rotation Interaction: Investigations of $^{13}$CH$_3$CN and CH$_3$$^{13}$CN up to $v_8 = 2$ and a Search for $v_8 = 2$ Transitions toward Sagittarius B2(N)
Universität zu Köln（科隆大学）；Max-Planck-Institut für Radioastronomie（马克斯·普朗克射电天文研究所）
