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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Pragmatic Many-Body Approach for Economic MP2 Energy Estimation of Molecular Clusters
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Pragmatic Many-Body Approach for Economic MP2 Energy Estimation of Molecular Clusters

机译：务实的多体方法，用于经济MP2的分子集群能量估计

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摘要

We propose a procedure, within the many-body analysis (MBA) framework, for an economic yet accurate estimation of the correlated method-based energies of large molecular clusters employing Dunning's augmented basis sets. The basis of the procedure is to segregate the Hartree-Fock (E-HF) and correlation energy (E-C) estimations. E-HF is found to differ by tens of millihartrees (mH) from its full-calculation (FC) counterpart on truncating the MBA expansion at the two-body (MBA-2) level. On the contrary, E-C is estimated with smaller error on modest hardware with limited computation time at the (MBA-2) level. In view of this, we adopt a pragmatic method wherein the EHF (accurate to five decimal places) is taken from the FC, whereas E-C is estimated at the MBA-2 level. This method is applied to a variety of medium to large molecular clusters at the MP2 level. Preliminary results at the CCSD(T) level for (H2O)(16) and (H2O)(17) are also reported with tremendous savings in wall-clock time and resources. The typical errors in MP2 and CCSD(T) energies per monomer are up to 0.1 and 0.2 mH, respectively. Thus the present method, balancing accuracy and computational economy, opens a way for estimating energies of large molecular clusters using correlated theories with large basis sets.
机译：我们提出了一种程序，在许多身体分析（MBA）框架内，用于经济而准确地估计，估计采用Dunning的增强基集的大分子集群的相关方法的能量。该过程的基础是分离Hartree-Fock（E-HF）和相关能量（E-C）估计。发现E-HF在其全计算（FC）对应物上有数十万毫升（MH）在双体（MBA-2）水平上截断MBA扩展的全部计算（FC）对应。相反，E-C估计，在适度的硬件上具有较小的错误，在（MBA-2）级别具有有限的计算时间。鉴于此，我们采用一种务实的方法，其中eHF（准确到五个小数位）取自Fc，而E-C估计在MBA-2水平。该方法应用于MP2水平的各种培养基到大分子簇。在CCSD（T）水平的初步结果（H2O）（16）和（H2O）（17）的初步结果也被报告，墙钟时间和资源巨大地节省。 MP2和CCSD（T）每个单体的典型误差分别高达0.1和0.2mH。因此，目前的方法，平衡精度和计算经济，开启了使用具有大基板的相关理论来估计大分子集群的能量。

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