Ab initio molecular orbital studies of low-energy, metastable isomers of the ubiquitous cyclopropenylidene
Ab initio molecular orbital studies of low-energy, metastable isomers of the ubiquitous cyclopropenylidene
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普遍存在的亚环丙烯的低能亚稳态异构体的从头算分子轨道研究
DOI：
10.1086/184738
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
McLean Ad
中科院分区：
文献类型：
--
作者：
D. Dj;McLean Ad
环丙烯叉在空间中的发现表明，其他C3 H2异构体可能存在，并已报告了一种这样的异构体，炔丙基（HCCCH）的初步检测。用从头算分子轨道理论研究了环丙烯叉的五种低位置亚稳异构体。四个被发现是稳定的极小值和他们的振动频率的报告，虽然稳定的三重态炔丙基的形式是没有牢固地建立。包括电子相关能的扩展计算表明，能量最低的是单重态propadienylidene，其次是炔丙基;后者的单重态和三重态的能量太接近，无法分配基态;三重态propadienylidene是在一个显着更高的能量。旋转频率计算的预期精度为+/- 1%-2%，并没有证实在太空中初步检测到炔丙基，尽管理论和观测之间的差异并没有大到可以明确排除这种可能性。
: The discovery of cyclopropenylidene in space suggests that other C3H2 isomers may be present and a tentative detection of one such isomer, propargylene (HCCCH), has been reported. Ab initio molecular orbital theory has been used to characterize five low-lying, metastable isomers of cyclopropenylidene. Four are found to be stable minima and their vibrational frequencies are reported, although the stable form of triplet propargylene is not firmly established. Extended calculations including the electron correlation energy, show that the lowest in energy is singlet propadienylidene, followed by propargylene; the singlet and triplet of the latter are too close in energy to allow an assignment of the ground state; triplet propadienylidene is at a significantly higher energy. Rotational frequencies computed to an expected accuracy of +/- 1%-2% do not confirm the tentative detection of propargylene in space, although the discrepancy between theory and the observation is not so great as to unequivocally rule out this possibility.