Laws Benjamin A, Levey Zachariah D, Schmidt Timothy W, Gibson Stephen T
School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia.
J Am Chem Soc. 2021 Nov 10;143(44):18684-18692. doi: 10.1021/jacs.1c08762. Epub 2021 Nov 2.
Weakly bound anionic systems present a new domain for negative ion spectroscopy. Here we report on a multifaceted study of the CHCN dipole-bound state, employing high-resolution photoelectron spectroscopy from 130 different wavelengths, velocity-map imaging at threshold, and laser scanning photodetachment experiments. This uncovers a wide variety of different vibrational and rotational autodetaching resonances. By examination of both sides of the problem, absorption from the anion to the dipole-bound state and vibrational/rotational autodetachment to the neutral, a complete model of the dipole-bound chemistry is formed. Precise values for the electron affinity EA = 12468.9(1) cm, dipole binding energy = 40.2(3) cm, and anion inversion splitting ω = 115.9(2) cm are obtained. This model is then employed to study possible astronomical implications, revealing good agreement between the = 1 ← 0 CHCN dipole transition and the λ8040 diffuse interstellar band.
弱束缚阴离子体系为负离子光谱学提供了一个新领域。在此，我们报告了对CHCN偶极束缚态的多方面研究，采用了来自130个不同波长的高分辨率光电子能谱、阈值处的速度成像以及激光扫描光剥离实验。这揭示了各种各样不同的振动和转动自解离共振。通过研究问题的两个方面，即从阴离子到偶极束缚态的吸收以及到中性态的振动/转动自解离，形成了偶极束缚化学的完整模型。获得了电子亲和能EA = 12468.9(1) cm、偶极结合能 = 40.2(3) cm以及阴离子反转分裂ω = 115.9(2) cm的精确值。然后利用该模型研究可能的天文学意义，结果表明 = 1 ← 0 CHCN偶极跃迁与λ8040弥漫星际带之间具有良好的一致性。
