Liu Gaoxiang, Ciborowski Sandra M, Pitts Cody Ross, Graham Jacob D, Buytendyk Allyson M, Lectka Thomas, Bowen Kit H
Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA.
Phys Chem Chem Phys. 2019 Aug 21;21(33):18310-18315. doi: 10.1039/c9cp04010b.
Quadrupole-bound anions are negative ions in which their excess electrons are loosely bound by long-range electron-quadrupole attractions. Experimental evidence for quadrupole-bound anions has been scarce; until now, only trans-succinonitrile had been experimentally confirmed to form a quadrupole-bound anion. In this study, we present experimental evidence for a new quadrupole-bound anion. Our combined Rydberg electron transfer/anion photoelectron spectroscopy study demonstrates that the ee conformer of 1,4-dicyanocyclohexane (DCCH) supports a quadrupole-bound anion state, and that the cis-DCCH conformer forms a dipole-bound anion state. The electron binding energies of the quadrupole- and dipole-bound anions are measured as 18 and 115 meV, respectively, both of which are in excellent agreement with theoretical calculations by Sommerfeld.
四极束缚阴离子是一类负离子，其中多余的电子通过长程电子 - 四极相互作用而松散地结合。四极束缚阴离子的实验证据一直很稀少；到目前为止，只有反式丁二腈已通过实验证实能形成四极束缚阴离子。在本研究中，我们给出了一种新的四极束缚阴离子的实验证据。我们结合里德堡电子转移/阴离子光电子能谱研究表明，1,4 - 二氰基环己烷（DCCH）的ee构象支持一种四极束缚阴离子态，而顺式DCCH构象形成一种偶极束缚阴离子态。四极束缚阴离子和偶极束缚阴离子的电子结合能分别测得为18和115毫电子伏特，这两者与索末菲的理论计算结果都非常吻合。
