Departament de Química and Institut de Química Computacional, Universitat de Girona, Campus Montilivi, 17071 Girona, Catalunya, Spain.
J Chem Phys. 2009 Sep 7;131(9):094103. doi: 10.1063/1.3213193.
We report here a new empirical density functional that is constructed based on the performance of OPBE and PBE for spin states and S(N)2 reaction barriers and how these are affected by different regions of the reduced gradient expansion. In a previous study [Swart, Sola, and Bickelhaupt, J. Comput. Methods Sci. Eng. 9, 69 (2009)] we already reported how, by switching between OPBE and PBE, one could obtain both the good performance of OPBE for spin states and reaction barriers and that of PBE for weak interactions within one and the same (SSB-sw) functional. Here we fine tuned this functional and include a portion of the KT functional and Grimme's dispersion correction to account for pi-pi stacking. Our new SSB-D functional is found to be a clear improvement and functions very well for biological applications (hydrogen bonding, pi-pi stacking, spin-state splittings, accuracy of geometries, reaction barriers).
我们在此报告了一种新的经验密度泛函，该泛函是基于 OPBE 和 PBE 在自旋态和 S(N)2 反应势垒方面的表现以及这些表现如何受缩减梯度展开不同区域的影响而构建的。在之前的研究中[Swart、Sola 和 Bickelhaupt，J. Comput. Methods Sci. Eng. 9, 69（2009）]，我们已经报告了如何通过在 OPBE 和 PBE 之间切换，可以在同一个（SSB-sw）泛函中获得 OPBE 在自旋态和反应势垒方面的良好性能以及 PBE 在弱相互作用方面的性能。在这里，我们对该泛函进行了微调，并包含了一部分 KT 泛函和 Grimme 的色散校正，以考虑 pi-pi 堆积。我们的新 SSB-D 泛函是一个明显的改进，非常适用于生物应用（氢键、pi-pi 堆积、自旋态分裂、几何形状的准确性、反应势垒）。
