论文标题
当黄金还不够的时候：铂金标准的量子化学标准，$ n^7 $成本
When gold is not enough: platinum standard of quantum chemistry with $N^7$ cost
论文作者
论文摘要
在本文中，我们将降低的耦合群集形式主义扩展到了由于四倍激励引起的非著作能量校正的计算。拟议的形式主义有两个主要组成部分。第一个是使用塔克格式的四倍激发幅度的近似压缩。第二个是用于评估校正的修改功能，为确切振幅提供了完全相同的结果，但不太容易受到上述压缩引起的错误。我们在理论上和数字上都表明，所提出的方法的计算成本量表是系统大小的第七幂。使用一组小分子的参考结果，对该方法进行了校准，以提供几个百分比的能量校正。为了说明理论的潜力，我们计算了\ emph {ortho}/\ emph {meta} benzyne（c $ _6 $ h $ _4 $）的异构化能量和COPE重新排列的Bullvalene（C $ _ {10} $ H $ _ $ _ $ _ {10} $）的障碍高度。该方法保留了常规耦合群集形式主义的近黑色盒子性质，并且仅取决于一个控制精度的附加参数。
In this paper we extend the rank-reduced coupled-cluster formalism to the calculation of non-iterative energy corrections due to quadruple excitations. There are two major components of the proposed formalism. The first is an approximate compression of the quadruple excitation amplitudes using the Tucker format. The second is a modified functional used for evaluation of the corrections which gives exactly the same results for the exact amplitudes, but is less susceptible to errors resulting from the aforementioned compression. We show, both theoretically and numerically, that the computational cost of the proposed method scales as the seventh power of the system size. Using reference results for a set of small molecules, the method is calibrated to deliver relative accuracy of a few percent in energy corrections. To illustrate the potential of the theory we calculate the isomerization energy of \emph{ortho}/\emph{meta} benzyne (C$_6$H$_4$) and the barrier height for the Cope rearrangement in bullvalene (C$_{10}$H$_{10}$). The method retains a near-black-box nature of the conventional coupled-cluster formalism and depends on only one additional parameter that controls the accuracy.
