论文标题
CC3的新实施
A new and efficient implementation of CC3
论文作者
论文摘要
我们在电子结构程序$ e^t $中使用封闭的外壳耦合群集单打（CC3）进行了新的且有效的实现。渐近地，基态计算的迭代成本为$ 4n _ {\ text {v}}^{4} n _ {\ text {o}}^{3} $ flo point operations（flop）轨道分别。迭代求解激发能和过渡矩所需的雅各布和转置雅各布式变换，都需要$ 8n _ {\ text {v}}}^{4}^{4} n _ {\ text {\ text {o}}}}}^{3} $ flop。我们还实施了CC3的运动方程（EOM）过渡矩。 EOM过渡密度需要重新计算三元组振幅，因为$ n _ {\ text {v}}}^{3} n _ {\ text {o}}}^{3} {3} $ tensor并未存储在内存中。这将导致$ 10n _ {\ text {v}}^{4} n _ {\ text {\ text {o}}^{3} $ flop的非熟悉计算成本的基态密度和$ 26N _ {\ text {v}} n _}密度。将代码与CFOR，Dalton和PSI4中的CC3实现进行了比较。我们通过计算L-丙烯的价和核心激发态来证明实施的能力。
We present a new and efficient implementation of the closed shell coupled cluster singles and doubles with perturbative triples method (CC3) in the electronic structure program $e^T$. Asymptotically, a ground state calculation has an iterative cost of $4n_{\text{V}}^{4}n_{\text{O}}^{3}$ floating point operations (FLOP), where $n_{\text{V}}$ and $n_{\text{O}}$ are the number of virtual and occupied orbitals respectively. The Jacobian and transpose Jacobian transformations, required to iteratively solve for excitation energies and transition moments, both require $8n_{\text{V}}^{4}n_{\text{O}}^{3}$ FLOP. We have also implemented equation of motion (EOM) transition moments for CC3. The EOM transition densities require recalculation of triples amplitudes, as $n_{\text{V}}^{3}n_{\text{O}}^{3}$ tensors are not stored in memory. This results in a noniterative computational cost of $10n_{\text{V}}^{4}n_{\text{O}}^{3}$ FLOP for the ground state density and $26n_{\text{V}}^{4}n_{\text{O}}^{3}$ FLOP per state for the transition densities. The code is compared to the CC3 implementations in CFOUR, Dalton and Psi4. We demonstrate the capabilities of our implementation by calculating valence and core excited states of L-proline.
