Abstract Rotational transitions of cis -glyoxal, C 2 H 2 O 2 , and its monodeuterated isotopomer have been detected by microwave spectroscopy, both in their vibrational ground states and in their first and second excited torsional ν 7 , as well as in their first excited ν 5 bending states. Assignments have been extended to high J and K a quantum numbers which leads to higher accuracy of the spectroscopic
摘要 顺式乙二醛、C 2 H 2 O 2 及其单氘同位素异构体的旋转跃迁已被微波光谱检测到,在它们的振动基态和它们的第一和第二激发扭转 ν 7 以及它们的第一激发ν 5 弯曲状态。分配已扩展到高 J 和 K a 量子数,这导致光谱参数的准确度高于迄今为止文献中已知的准确度。在乙二醛光谱中已经观察到 v 7 = 1 的 335 kHz 和 v 7 = 2 的 42.6 MHz 扭转振动水平的隧道分裂。由于对称性原因,正如预期的那样,乙二醛-d 1 中不存在这些分裂,而在所有光谱中偶尔会看到局部扰动。已经确定了两种分子在几种振动状态下的电偶极矩分量,其中在所有情况下都发现 μ b 值接近 3.40 D。顺式-反式焓差Δ H = (18.60 ± 0.57) kJ mol -1 ((1555 ± 48) cm -1 ),由乙二醛和乙二醛-d 1 相对于 OCS 分子的吸收强度确定。使用 Δ H
The equilibrium structure of trans-glyoxal from experimental rotational constants and calculated vibration–rotation interaction constants
isotopologues using the Watson Hamiltonian in A-reduction and Ir-representation the ground state rotationalconstants are obtained. An empirical equilibrium structure is determined for trans-glyoxal using these experimental ground state rotationalconstants and vibration–rotation interaction constants calculated at the CCSD(T)/cc-pVTZ level of theory. The least-squares fit yields the following structural
记录了 trans-glyoxal-d2、trans-glyoxal-d1 和 trans-glyoxal-13C2 的 6 个高分辨率 FT-IR 光谱,分辨率范围为 0.003 至 0.004 cm-1。通过在 A 还原和 Ir 表示中使用沃森哈密顿量对这些同位素中的每一个进行同时基态组合差异分析,获得了基态旋转常数。使用在 CCSD(T)/cc-pVTZ 理论水平计算的这些实验基态旋转常数和振动-旋转相互作用常数确定反式乙二醛的经验平衡结构。最小二乘拟合得出反式乙二醛的以下结构参数:re(C–C) = 1.51453(38) A, re(C–H) = 1.10071(26) A, re(CO) = 1.20450(27) A,αe(CCH) = 115.251(24)°,αe(HCO) = 123。