论文标题
加速的耦合群集计算与procrustes轨道插值
Accelerated coupled cluster calculations with Procrustes orbital interpolation
论文作者
论文摘要
耦合簇方法被认为是量子化学中的金标准，可靠地提供了在化学精度（1.6 mhartree）内精确的能量。但是，即使在CCSD近似中，将群集运算符截断以仅包含单个和双重激发，该方法的电子数量为$ O（n^6）$，并且需要对迭代依次求解群集操作员，从而增加了计算时间。受特征向量延续的启发，我们在这里提出了一种利用高斯流程的算法，该过程为耦合群集振幅提供了改进的初始猜测。群集操作员以在特定样品几何形状上获得的样品簇运算符的线性组合写入。通过以这种方式从先前的计算中重用群集运算符，可以从超过MP2猜测和“以前的几何形状” - guesses的振幅开始猜测，从必要的迭代次数来看。由于这种改进的猜测非常接近确切的群集操作员，因此可以直接用于将CCSD能量计算为化学精度，从而使CCSD能量缩放为$ O（n^5）$。
The coupled cluster method is considered a gold standard in quantum chemistry, reliably giving energies that are exact within chemical accuracy (1.6 mHartree). However, even in the CCSD approximation, where the cluster operator is truncated to include only single and double excitations, the method scales as $O(N^6)$ in the number of electrons, and the cluster operator needs to be solved for iteratively, increasing computation time. Inspired by eigenvector continuation, we present here an algorithm making use of Gaussian processes that provides an improved initial guess for the coupled cluster amplitudes. The cluster operator is written as a linear combination of sample cluster operators which are obtained at particular sample geometries. By reusing the cluster operators from previous calculations in that way, it is possible to obtain a start guess for the amplitudes that surpasses both MP2-guesses and "previous geometry"-guesses in terms of the number of necessary iterations. As this improved guess is very close to the exact cluster operator, it can be used directly to calculate the CCSD energy to chemical accuracy, giving approximate CCSD energies scaling as $O(N^5)$.
