发表机构
Capgemini Quantum Lab; IBM T. J. Watson Research Center; Q-CTRL（凯捷量子实验室; IBM托马斯·J·沃森研究中心; Q-CTRL）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究开壳层3d过渡金属配合物，结合基于样本的量子对角化（SQD）与积分方程形式的极化连续介质模型（IEF-PCM），利用IBM Heron量子处理器样本及高达50个量子比特的心空间，再现基准，解决避免交叉，展示了SQD用于此类配合物的有效性。
AI 中文摘要
开壳层3d过渡金属配合物对电子结构方法提出挑战，因为竞争自旋态、电荷转移和溶剂化共同决定其能量。本文将基于样本的量子对角化（SQD）与积分方程形式的极化连续介质模型（IEF-PCM）相结合，将SQD扩展到介电环境中的相关开壳层过渡金属系统。研究了八面体配位的[Co(H₂O)₅CO₂]²⁺/³⁺配合物在两个氧化态、四个自旋多重度和一个金属-配体解离坐标下的情况。通过外部自洽反应场循环将开壳层参考纳入SQD-IEF-PCM。利用在IBM Heron量子处理器上收集的样本和高达50个量子比特的心空间，SQD在气相和隐式溶剂中在相同心空间内再现了耦合簇和热浴配置相互作用基准，最大观察偏差低于9 mEₕ。沿着高自旋五重态[Co(H₂O)₅CO₂]³⁺的解离坐标，SQD解决了由内部电荷转移引起的避免交叉；单重态和较低氧化态的配合物中不存在此特征。相对于气相，隐式溶剂化使五重态的中性CO₂解离稳定并抑制了避免交叉特征。这是首次在硬件上展示SQD用于气相和隐式溶剂中的开壳层3d过渡金属配合物。这些结果确立了SQD作为一种强大的以量子为中心的方法用于过渡金属化学，其中自旋态排序、电荷转移和环境效应紧密交织。
英文摘要
Open-shell $3d$ transition-metal complexes pose a stringent challenge for correlated electronic-structure methods because near-degenerate metal $d$ orbitals give rise to competing spin states and oxidation-state-dependent charge transfer, while solvation can reshape the relative stability of the resulting electronic configurations. Building on prior demonstrations of open-shell sample-based quantum diagonalization (SQD) for light-atom systems and, separately, closed-shell SQD coupled to the integral-equation-formalism polarizable continuum model (IEF-PCM), we combine these capabilities through an open-shell SQD--IEF-PCM framework and apply it to the octahedrally coordinated $\mathrm{[Co(H_2O)_5CO_2]^{2+/3+}}$ complex, spanning the Co(III) singlet and quintet and Co(II) doublet and quartet states along a metal--ligand dissociation coordinate. Using quantum samples collected on an IBM Heron processor and active spaces of up to 50 qubits, SQD closely reproduces coupled-cluster and heat-bath configuration-interaction benchmarks within the same active spaces in both gas phase and implicit solvent; for high-spin quintet $\mathrm{[Co(H_2O)_5CO_2]^{3+}}$, it additionally resolves an avoided crossing associated with internal charge transfer that is absent in the corresponding singlet and in the lower oxidation state, while IEF-PCM suppresses this crossover by preferentially stabilizing the dissociation channel leading to neutral CO$_2$. To our knowledge, this work provides the first hardware demonstration of SQD for an open-shell 3d transition-metal complex with discrete metal-centered d-orbital chemistry, and the first application of open-shell SQD in a dielectric continuum, establishing a quantum-centric framework for transition-metal chemistry in regimes where spin-state energetics, charge transfer, and environmental response are strongly coupled.
Comments40 pages, 20 figures, 8 tables
