AI 中文总结
本文提出SVD-TC方案，通过SVD压缩TC计算的虚拟空间，将其应用于G2-1集，实现高效高精度的原子化能计算，且赝势TC基组收敛更快。
AI 中文摘要
我们提出了一种新的基于奇异值分解（SVD）的方案，用于为关联电子（TC）计算从大基组构建小型虚拟空间，该方案命名为SVD-TC。本研究基于近期发现：TC参考能量中的残差基组误差收敛速度慢于关联能量。在新工作流程中，后哈特利-福克（post Hartree-Fock）TC计算在压缩后的虚拟轨道子空间中进行，该子空间通过奇异值分解（SVD）将大基组的正则虚拟轨道投影到更小的基组上得到。这使我们能够达到大基组允许的高精度，同时瓶颈步骤——TC积分计算和后HF关联方法（如CCSD(T)）——仅产生小型虚拟空间计算的成本，因此该方法效率极高，且避免了参考校正方法的复合性质。使用新方案，我们将基准质量TC结果的范围扩展到比之前考虑的更复杂的分子：对包含第一和第二周期原子的55个分子的G2-1集，我们应用SVD-xTC-CCSD(T)计算原子化能，并将结果与近乎精确的半随机热浴组态相互作用（SHCI）参考值和实验值进行比较。我们发现SVD-xTC-CCSD(T)在双-ζ基组下已达到化学精度。最后，我们利用四-ζ结果分析TC方法中赝势的精度，表明赝势TC工作流程比全电子TC具有更快的基组收敛速度。我们还给出了G2-1集原子化能计算的时间，证明了TC工作流程的效率。
英文摘要
We introduce a new singular-value-decomposition-based scheme for constructing small virtual spaces out of large basis sets for transcorrelated (TC) calculations, termed SVD-TC. This work builds on the recent finding that the residual basis error in the TC reference energy converges more slowly than that of the correlation energy. Within the new workflow, the post Hartree-Fock TC calculation is performed in a compressed virtual orbital subspace, obtained by projecting the canonical virtual orbitals from a large basis set onto a smaller basis set through singular value decomposition (SVD). This allows us to achieve the high accuracy allowed by the large basis, whilst the bottleneck steps - TC integral calculation and post-HF correlation method such as CCSD(T) - incur the cost of only a small virtual space calculation. The method therefore is highly efficient, whilst avoiding the composite nature of the reference correction method. Using the new scheme, we widen the scope of benchmark-quality TC results into more complex molecules than previously considered: using the G2-1 set of 55 molecules with first- and second-row atoms, we apply SVD-xTC-CCSD(T) to compute atomization energies. We compare our results against the near-exact semistochastic heat-bath configuration interaction (SHCI) reference values and experiment. We find that SVD-xTC-CCSD(T) delivers chemical accuracy already with triple-$ζ$ basis sets. Finally, we use the quadruple-$ζ$ results to analyze the accuracy of pseudopotentials within the TC method, and show that pseudopotential TC workflow provides faster basis-set convergence than all-electron TC. We also present timings for computing the atomization energies on G2-1 set, demonstrating the efficiency of our TC workflows.
