Characterising molecules for fundamental physics: an accurate spectroscopic model of methyltrioxorhenium derived from new infrared and millimetre-wave measurements
Characterising molecules for fundamental physics: an accurate spectroscopic model of methyltrioxorhenium derived from new infrared and millimetre-wave measurements
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DOI：
10.1039/c6cp08724h
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发表时间：
2017-02-14
影响因子：
3.3
通讯作者：
Darquie, Benoit
中科院分区：
文献类型：
--
作者：
Asselin, Pierre;Berger, Yann;Darquie, Benoit
多原子分子的精确光谱分析使物理化学和基础物理学取得了许多惊人的进展。我们使用几种新的高分辨率光谱设备，以提高我们的旋转和振转结构的甲基三氧化铼（MTO），一个家庭的大oxorhenium化合物的理想候选物种的计划测量的奇偶违反手性分子的非手性父。使用毫米波和红外光谱在脉冲超音速射流，低温缓冲气体电池，和室温吸收电池，我们探测基态和Re=O反对称和对称拉伸激发态的（CH 3ReO 3）-Re-187和（CH 3ReO 3）-Re-185同位素在气相中前所未有的精度。通过扩展的旋转光谱到150-300 GHz的范围内，我们表征的基态旋转和超精细结构高达J = 43和K = 41，从而细化的旋转，四次和超精细参数，和六次参数的测定和离心畸变校正的四极超精细常数。我们获得的振转数据的温度在6和300 K之间，在970-1015厘米（-1）的范围内，在分辨率下降到8 MHz和30 MHz的精度。我们使用这些数据来确定更精确的激发态旋转，科里奥利和四次参数，以及基态离心畸变参数D-K的Re-187同位素。我们还考虑了振转跃迁中的超精细结构，从而确定了上态双原子四极耦合常数eQq '。
Precise spectroscopic analysis of polyatomic molecules enables many striking advances in physical chemistry and fundamental physics. We use several new high-resolution spectroscopic devices to improve our understanding of the rotational and rovibrational structure of methyltrioxorhenium (MTO), the achiral parent of a family of large oxorhenium compounds that are ideal candidate species for a planned measurement of parity violation in chiral molecules. Using millimetre-wave and infrared spectroscopy in a pulsed supersonic jet, a cryogenic buffer gas cell, and room temperature absorption cells, we probe the ground state and the Re=O antisymmetric and symmetric stretching excited states of both (CH3ReO3)-Re-187 and (CH3ReO3)-Re-185 isotopologues in the gas phase with unprecedented precision. By extending the rotational spectra to the 150-300 GHz range, we characterize the ground state rotational and hyperfine structure up to J = 43 and K = 41, resulting in refinements to the rotational, quartic and hyperfine parameters, and the determination of sextic parameters and a centrifugal distortion correction to the quadrupolar hyperfine constant. We obtain rovibrational data for temperatures between 6 and 300 K in the 970-1015 cm(-1) range, at resolutions down to 8 MHz and accuracies of 30 MHz. We use these data to determine more precise excited-state rotational, Coriolis and quartic parameters, as well as the ground-state centrifugal distortion parameter D-K of the Re-187 isotopologue. We also account for hyperfine structure in the rovibrational transitions and hence determine the upper state rhenium atom quadrupole coupling constant eQq'.