Parametrization and Benchmark of DFTB3 for Organic Molecules
Parametrization and Benchmark of DFTB3 for Organic Molecules
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DOI：
10.1021/ct300849w
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发表时间：
2013-01-01
影响因子：
5.5
通讯作者：
Elstner, Marcus
中科院分区：
文献类型：
--
作者：
Gaus, Michael;Goez, Albrecht;Elstner, Marcus
DFTB3是自洽电荷密度泛函紧密结合方法（SCC-DFTB）的最新扩展，由密度泛函理论（DFT）总能量围绕给定参考密度的三阶展开推导而来。DFTB3与先前的参数化（MIO）结合使用，提高了氢结合能、质子亲和和氢转移势垒。在本研究中，提出了专门为DFTB3设计的参数，并从我们自己的数据库和文献中的几个数据库中评估了DFTB3在小有机分子中的性能，重点是热化学、几何形状和振动频率。新参数消除了显著的过结合误差，减少了非共价相互作用的几何误差，并提高了整体性能。
DFTB3 is a recent extension of the self-consistent-charge density-functional tight-binding method (SCC-DFTB) and derived from a third order expansion of the density functional theory (DFT) total energy around a given reference density. Being applied in combination with the parametrization of its predecessor (MIO), DFTB3 improves for hydrogen binding energies, proton affinities, and hydrogen transfer barriers. In the present study, parameters especially designed for DFTB3 are presented, and its performance is evaluated for small organic molecules focusing on thermochemistry, geometries, and vibrational frequencies from our own and several databases from literature. The new parameters remove significant overbinding errors, reduce errors for geometries of noncovalent interactions, and improve the overall performance.