Institut für Physikalische Chemie, Tammannstr. 6, Georg-August-Universität, D-37077 Göttingen, Germany.
J Phys Chem A. 2011 Jun 16;115(23):6068-76. doi: 10.1021/jp110584s. Epub 2011 Mar 15.
Ethanol clusters are generated in a continuous He seeded supersonic expansion and doped with sodium atoms in a pick-up cell. By this method clusters of the type Na(C(2)H(5)OH)(n) are formed and characterized by determining size selectively their ionization potentials (IPs) for n = 2-40 in photoionization experiments. A continuous decrease to 3.1 eV is found from n = 2 to 6 and a constant value of 3.07 ± 0.06 eV for n = 10-40. This IP evolution is similar to the sodium-water and the sodium-methanol system. Quantum chemical calculations (B3LYP and MP2) of the IPs indicate adiabatic contributions to the photoionization process for the cluster sizes n = 4 and 5, which is similar to the sodium-methanol case. The results of the extrapolated IPs and the vertical binding energies (VEBs) of cluster anions are compared with the recently reported VEBs of solvated electrons in liquid water, methanol, and ethanol solutions in the range of 3.1-3.4 eV. The new results imply that the extrapolated VBEs of solvated electrons in anionic clusters match the VBE in liquid water, while they are about 0.5 eV too low for methanol. The influence of the presence of counterions on these findings is discussed.
乙醇团簇在连续的氦种子超音速膨胀中生成，并在提升池中用钠原子掺杂。通过这种方法，可以形成 Na(C(2)H(5)OH)(n) 类型的团簇，并通过光致电离实验确定其大小选择性的电离势 (IP) 来对 n = 2-40 进行表征。从 n = 2 到 6 发现连续下降到 3.1 eV，而对于 n = 10-40 则保持 3.07 ± 0.06 eV 的恒定值。这种 IP 演化与钠-水和钠-甲醇体系相似。对 IPs 的量子化学计算 (B3LYP 和 MP2) 表明，对于 n = 4 和 5 的团簇尺寸，光致电离过程存在绝热贡献，这与钠-甲醇情况相似。外推的 IPs 和团簇阴离子的垂直结合能 (VEB) 的结果与最近报道的在 3.1-3.4 eV 范围内的液态水、甲醇和乙醇溶液中溶剂化电子的 VEB 进行了比较。新结果表明，阴离子团簇中溶剂化电子的外推 VBE 与液态水中的 VBE 相匹配，而对于甲醇则低约 0.5 eV。讨论了抗衡离子的存在对这些发现的影响。
