Simpson Malcolm, Nötzold Markus, Schmidt-May Alice, Michaelsen Tim, Bastian Björn, Meyer Jennifer, Wild Robert, Gianturco Franco A, Milovanović Milan, Kokoouline Viatcheslav, Wester Roland
Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
University of Belgrade, Faculty of Physical Chemistry, Studentski trg 12-16, P.O. Box 47, 11158 Belgrade, Serbia.
J Chem Phys. 2020 Nov 14;153(18):184309. doi: 10.1063/5.0029841.
Threshold photodetachment spectroscopy has been performed on the molecular anion CN at both 16(1) K and 295(2) K in a 22-pole ion trap and at 295(2) K from a pulsed ion beam. The spectra show a typical energy dependence of the detachment cross section yielding a determination of the electron affinity of CN to greater precision than has previously been known at 31 163(16) cm [3.864(2) eV]. Allowed s-wave detachment is observed for CN, but the dependence of the photodetachment cross section near the threshold is perturbed by the long-range interaction between the permanent dipole moment of CN and the outgoing electron. Furthermore, we observe a temperature dependence of the cross section near the threshold, which we attribute to a reduction of the effective permanent dipole due to higher rotational excitation at higher temperatures.
已在22极离子阱中于16(1)K和295(2)K以及在295(2)K下从脉冲离子束对分子阴离子CN进行了阈光致脱附光谱研究。光谱显示了脱附截面典型的能量依赖性，从而确定了CN的电子亲和能，其精度高于此前已知的31163(16)cm⁻¹[3.864(2)eV]。观察到CN发生允许的s波脱附，但阈附近光致脱附截面的依赖性受到CN永久偶极矩与出射电子之间长程相互作用的干扰。此外，我们观察到阈附近截面的温度依赖性，我们将其归因于较高温度下更高的转动激发导致有效永久偶极矩的减小。
