Dong Geng, Ryde Ulf, Aa Jensen Hans Jørgen, Hedegård Erik D
Department of Theoretical Chemistry, Lund University, Chemical Centre, P. O. Box 124, SE-221 00 Lund, Sweden.
Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark.
Phys Chem Chem Phys. 2018 Jan 3;20(2):794-801. doi: 10.1039/c7cp06767d.
The combination of density functional theory (DFT) with a multiconfigurational wave function is an efficient way to include dynamical correlation in calculations with multiconfiguration self-consistent field wave functions. These methods can potentially be employed to elucidate reaction mechanisms in bio-inorganic chemistry, where many other methods become either too computationally expensive or too inaccurate. In this paper, a complete active space (CAS) short-range DFT (CAS-srDFT) hybrid was employed to investigate a bio-inorganic system, namely H binding to the active site of [NiFe] hydrogenase. This system was previously investigated with coupled-cluster (CC) and multiconfigurational methods in the form of cumulant-approximated second-order perturbation theory, based on the density matrix renormalization group (DMRG). We find that it is more favorable for H to bind to Ni than to Fe, in agreement with previous CC and DMRG calculations. The accuracy of CAS-srDFT is comparable to both CC and DMRG, despite much smaller active spaces were employed than in the corresponding DMRG calculations. This enhanced efficiency at the smaller active spaces shows that CAS-srDFT can become a useful method for bio-inorganic chemistry.
密度泛函理论（DFT）与多组态波函数相结合，是在多组态自洽场波函数计算中纳入动态相关的一种有效方法。这些方法有可能用于阐明生物无机化学中的反应机理，而在这一领域，许多其他方法要么计算成本过高，要么不够精确。本文采用一种完全活性空间（CAS）短程DFT（CAS-srDFT）杂化方法，研究了一个生物无机体系，即氢与[NiFe]氢化酶活性位点的结合。此前，基于密度矩阵重整化群（DMRG），采用累积量近似二阶微扰理论形式的耦合簇（CC）和多组态方法对该体系进行了研究。我们发现，氢与镍结合比与铁结合更有利，这与之前的CC和DMRG计算结果一致。尽管所采用的活性空间比相应的DMRG计算小得多，但CAS-srDFT的精度与CC和DMRG相当。在较小活性空间下这种提高的效率表明，CAS-srDFT可以成为生物无机化学中一种有用的方法。
