Photoelectron spectroscopy of pyridine cluster anions, (Py)n-(n=4-13)
Photoelectron spectroscopy of pyridine cluster anions, (Py)n-(n=4-13)
复制标题
DOI：
10.1063/1.480269
复制
发表时间：
1999-09-01
影响因子：
4.4
通讯作者：
Kim, SK
中科院分区：
文献类型：
--
作者：
Han, SY;Song, JK;Kim, SK
对吡啶（C_5H_5N =Py）~（Py）（13）（-）的质量选择性阴离子团簇进行了光电子能谱研究。观察到的最小阴离子簇是（Py）（4）（-），其表现出由偶极束缚电子态和价电子态产生的两个明显不同的光电子带。[（Py）（3）（H2O）（1）]（-）的混合簇合物也显示出类似的特征。在大的纯吡啶团簇（Py）（5-13）（-）中没有观察到偶极束缚态，这被解释为吡啶分子阴离子的溶剂化团簇，Py-（Py）（4-12-）的阈值电子结合能被测量为绝热电子亲合势的上限值。它们单调增加，从0.33 eV的集群大小为n=4至1.02 eV的n=13。但是它们的增量变化在n=8时显示出大的下降，垂直脱离能的增量变化也是如此，这被认为是由于n=7时第一溶剂化壳层的完成。阴离子溶剂化的能量学表明几乎纯粹的静电相互作用在起作用。在吡啶分子的绝热电子亲合势上画出-0.67至-0.15eV之间的边界。在一个非常高的激光能量密度条件下，发现发生多光子过程，导致光致碎裂，然后光剥离。（Py）（5，6）（-）的光致碎裂产生的光致碎片显示出与（Py）（4）（-）的偶极束缚态相同的特征。这被认为是在这些较大的团簇中存在扩散轨道性质的偶极束缚激发态的证据。(C)1999年美国物理学会。[S0021-9606（99）00733-3]。
Photoelectron spectroscopy was carried out for mass-selected anion clusters of pyridine (C5H5N=Py) up to (Py)(13)(-). The smallest anion cluster observed was (Py)(4)(-) , which exhibited two distinctly different photoelectron bands arising from dipole-bound and valence electron states. A mixed cluster of [(Py)(3)(H2O)(1)](-) displayed similar features. No dipole-bound state was observed in the larger clusters of neat pyridine, (Py)(5-13)(-), which were interpreted as solvated clusters of pyridine molecular anion, Py-(Py)(4-12-) Threshold electron binding energies were measured as the upper limit value of adiabatic electron affinities. They increased monotonically from 0.33 eV for the cluster size of n=4 to 1.02 eV for n=13. But their incremental change showed a large drop at n=8, as did the incremental change in vertical detachment energy, which was viewed as due to the completion of the first solvation shell at n=7. The energetics of anion solvation suggested nearly pure electrostatic interactions at play. A boundary was drawn on the adiabatic electron affinity of the pyridine molecule between -0.67 and -0.15 eV. Under a very high laser fluence condition, multiphoton processes were found to occur that lead to photofragmentation followed by photodetachment. Photofragmentation of (Py)(5,6)(-) yielded photofragments which revealed the same features as the dipole-bound state of (Py)(4)(-). This was taken as evidence for the existence of dipole-bound excited states of diffuse orbital character in these larger clusters. (C) 1999 American Institute of Physics. [S0021-9606(99)00733-3].