Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA.
J Phys Chem B. 2012 Jun 21;116(24):7269-80. doi: 10.1021/jp301925k. Epub 2012 May 4.
The effect of hydration on the lowest vertical ionization energy (VIE) of phenol and phenolate solvated in bulk water was characterized using the equation-of-motion ionization potential coupled-cluster (EOM-IP-CCSD) and effective fragment potential (EFP) methods (referred to as EOM/EFP) and determined experimentally by valence photoemission measurements using microjets and synchrotron radiation. The computed solvent-induced shifts in VIEs (ΔVIEs) are -0.66 and +5.72 eV for phenol and phenolate, respectively. Our best estimates of the absolute values of VIEs (7.9 and 7.7 eV for phenol and phenolate) agree reasonably well with the respective experimental values (7.8 ± 0.1 and 7.1 ± 0.1 eV). The EOM/EFP scheme was benchmarked against full EOM-IP-CCSD using microsolvated phenol and phenolate clusters. A protocol for calculating redox potentials with EOM/EFP was developed based on linear response approximation (LRA) of free energy determination. The oxidation potentials of phenol and phenolate calculated using LRA and EOM/EFP are 1.32 and 0.89 V, respectively; they agree well with experimental values.
采用运动方程离子化势能耦合簇（EOM-IP-CCSD）和有效片段势能（EFP）方法（简称 EOM/EFP），并通过微射流和同步辐射的价光电发射测量实验确定了水合作用对苯酚和酚盐在体相水中的最低垂直离子化能（VIE）的影响。计算得到的 VIE 溶剂诱导位移（ΔVIE）分别为苯酚和酚盐的-0.66 和+5.72 eV。我们对 VIE 的绝对值的最佳估计值（苯酚和酚盐分别为 7.9 和 7.7 eV）与各自的实验值（7.8 ± 0.1 和 7.1 ± 0.1 eV）相当吻合。EOM/EFP 方案通过微溶剂化苯酚和酚盐簇与全 EOM-IP-CCSD 进行了基准测试。基于自由能确定的线性响应近似（LRA），开发了一种使用 EOM/EFP 计算氧化还原电势的方案。使用 LRA 和 EOM/EFP 计算得到的苯酚和酚盐的氧化电势分别为 1.32 和 0.89 V，与实验值吻合较好。
