A computational and spectroscopic study of MgCCH (X 2 Σ + ): towards characterizing MgCCH +
A computational and spectroscopic study of MgCCH (X 2 Σ + ): towards characterizing MgCCH +
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MgCCH (X 2 Σ ) 的计算和光谱研究：表征 MgCCH
DOI：
10.1080/00268976.2023.2267135
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发表时间：
2023
影响因子：
1.7
通讯作者：
Ziurys, Lucy M.
中科院分区：
文献类型：
--
作者：
Burns, Joseph E.;Cheng, Qianyi;Fortenberry, Ryan C.;Sun, Ming;Zack, Lindsay N.;Zaveri, Trishal;DeYonker, Nathan J.;Ziurys, Lucy M.
对MgCCH自由基的X2 π +态进行了新的计算和实验研究。用耦合团簇理论[CCSD（T）]结合后CCSD（T）修正和标量相对论加和修正计算了MgCCH及其阳离子的振动四次力场。从四次力场，高阶光谱特性，包括旋转常数，得到。在9-50 GHz频率范围内，利用傅里叶变换微波/毫米波方法首次测量了MgCCH的5个最低能量转动跃迁，N= 1→0 throughN= 5→4。自由基是在Ziurys集团开发的放电辅助激光烧蚀源（DALAS）中产生的。这些数据与以前的毫米直接吸收测量相结合的拟合产生了迄今为止最准确的旋转常数MgCCH。计算出的主转动常数与实验值相差在−1.51 ~+1.65 MHz之间，验证了计算方法的正确性。然后应用高级理论产生MgCCH+的振转光谱常数，包括B 0 = 5354.5-5359.5 MHz的转动常数。这些新的预测将进一步的MgCCH+的实验研究，并在星际介质中的MgCCH的低温特性援助。
New computational and experimental studies have been carried out for the MgCCH radical in its X2Σ+state. Coupled cluster theory [CCSD(T)], was used in conjunction with post-CCSD(T) and scalar relativistic additive corrections to compute vibrational quartic force fields for MgCCH and its cation. From the quartic force fields, higher-order spectroscopic properties, including rotational constants, were obtained. In tandem, the five lowest energy rotational transitions for MgCCH,N= 1→0 throughN= 5→4, were measured for the first time using Fourier transform microwave/millimetre wave methods in the frequency range 9–50 GHz. The radical was created in the Discharge Assisted Laser Ablation Source (DALAS) developed in the Ziurys group. A combined fit of these data with previous millimetre direct absorption measurements have yielded the most accurate rotational constants for MgCCH to date. The computed principle rotational constant lies within −1.51 to +1.65 MHz of the experimental one, validating the computational approach. High-level theory was then applied to produce rovibrational spectroscopic constants for MgCCH+, including a rotational constant of B0= 5354.5–5359.5 MHz. These new predictions will further the experimental study of MgCCH+, and aid in the low-temperature characterisation of MgCCH in the interstellar medium.