Tazhigulov Ruslan N, Bravaya Ksenia B
Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States.
J Phys Chem Lett. 2016 Jul 7;7(13):2490-5. doi: 10.1021/acs.jpclett.6b00893. Epub 2016 Jun 20.
Quantitative prediction of the energetics of redox half-reactions is still a challenge for modern computational chemistry. Here, we propose a simple scheme for reliable calculations of vertical ionization and attachment energies, as well as of redox potentials of solvated molecules. The approach exploits linear response approximation in the context of explicit solvent simulations with spherical boundary conditions. It is shown that both vertical ionization energies and vertical electron affinities, and, consequently redox potentials, exhibit linear dependence on the inverse radius of the solvation sphere. The explanation of the linear dependence is provided, and an extrapolation scheme is suggested. The proposed approach accounts for the specific short-range interactions within hybrid DFT and effective fragment potential approach as well as for the asymptotic system-size effects. The computed vertical ionization energies and redox potentials are in excellent agreement with the experimental values.
氧化还原半反应能量的定量预测仍是现代计算化学面临的一项挑战。在此，我们提出一种简单方案，用于可靠计算垂直电离能和电子亲合能，以及溶剂化分子的氧化还原电位。该方法在具有球形边界条件的显式溶剂模拟背景下利用线性响应近似。结果表明，垂直电离能和垂直电子亲合能，进而氧化还原电位，均与溶剂化球的逆半径呈线性依赖关系。文中给出了这种线性依赖关系的解释，并提出了一种外推方案。所提方法考虑了混合密度泛函理论（DFT）与有效片段势方法中的特定短程相互作用以及渐近体系尺寸效应。计算得到的垂直电离能和氧化还原电位与实验值高度吻合。
