Najeeb P K, Stockett M H, Anderson E K, Kristiansson M K, Reinhed P, Simonsson A, Rosén S, Thomas R D, Chartkunchand K C, Gnaser H, Golser R, Hanstorp D, Larson Å, Cederquist H, Schmidt H T, Zettergren H
Department of Physics, Stockholm University, AlbaNova, Stockholm SE-106 91, Sweden.
AMO Physics Laboratory, RIKEN Advanced Science Institute, Saitama 351-0198, Japan.
Phys Rev Lett. 2023 Sep 15;131(11):113003. doi: 10.1103/PhysRevLett.131.113003.
We have studied the stability of the smallest long-lived all carbon molecular dianion (C_{7}^{2-}) in new time domains and with a single ion at a time using a cryogenic electrostatic ion-beam storage ring. We observe spontaneous electron emission from internally excited dianions on millisecond timescales and monitor the survival of single colder C_{7}^{2-} molecules on much longer timescales. We find that their intrinsic lifetime exceeds several minutes-6 orders of magnitude longer than established from earlier experiments on C_{7}^{2-}. This is consistent with our calculations of vertical electron detachment energies predicting one inherently stable isomer and one isomer which is stable or effectively stable behind a large Coulomb barrier for C_{7}^{2-}→C_{7}^{-}+e^{-} separation.
我们利用低温静电离子束储存环，在新的时间尺度下，每次仅对单个离子进行研究，考察了最小的长寿命全碳分子双负离子（C₇²⁻）的稳定性。我们观察到内部激发的双负离子在毫秒时间尺度上会自发发射电子，并在长得多的时间尺度上监测单个较冷的C₇²⁻分子的存活情况。我们发现它们的固有寿命超过几分钟，比早期对C₇²⁻进行的实验所确定的寿命长6个数量级。这与我们对垂直电子脱离能的计算结果一致，该计算预测了一种固有稳定的异构体和一种在C₇²⁻→C₇⁻ + e⁻分离时，在大库仑势垒后稳定或有效稳定的异构体。
