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arXiv 2410.03410physics.chem-phphysics.comp-ph
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评估多体方法在(H$_2$)$_2$氢二聚体势能面上的表现

Assessing many-body methods on the potential energy surface of the (H$_2$)$_2$ hydrogen dimer

Damian Contant, Michele Casula, Maria Hellgren

AI总结:

本研究利用LRDMC和多种DFT近似泛函测定了(H$_2$)$_2$二聚体五种构型的势能曲线,发现多数DFT泛函在有限压缩下失效,仅在RPA中引入交换作用才能在整个势能曲线上获得定性正确的描述。

摘要:

(H$_2$)$_2$二聚体的各向异性势能面对多体方法而言是一个具有挑战性的问题。在此,我们利用晶格正则化扩散蒙特卡洛(LRDMC)方法以及密度泛函理论(DFT)中的多种近似泛函,包括基于随机相近似(RPA)的先进轨道依赖泛函,测定了五种不同二聚体构型(T、Z、X、H、L)的势能曲线。我们评估了它们在描述势阱、键长和相对能量方面的表现。通过研究不同二聚体构型在沿分子间轴施加外力作用下的相对稳定性,探讨了排斥势垒问题。结果表明,DFT中的大多数泛函在有限压缩下均会失效,即使是那些能准确描述势阱极小值附近区域的泛函也不例外。只有在RPA中引入交换作用,才能在整个势能曲线上获得定性正确的描述。最后,我们在有限压力下固态分子氢的背景下讨论了这些结果。

英文摘要:

The anisotropic potential energy surface of the (H$_2$)$_2$ dimer represents a challenging problem for many-body methods. Here, we determine the potential energy curves of five different dimer configurations (T, Z, X, H, L) using the lattice regularized diffusion Monte Carlo (LRDMC) method and a number of approximate functionals within density functional theory (DFT), including advanced orbital-dependent functionals based on the random phase approximation (RPA). We assess their performance in describing the potential wells, bond distances and relative energies. The repulsive potential wall is studied by looking at the relative stability of the different dimer configurations as a function of an applied force acting along the intermolecular axis. It is shown that most functionals within DFT break down at finite compression, even those that give an accurate description around the potential well minima. Only by including exchange within RPA a qualitatively correct description along the entire potential energy curve is obtained. Finally, we discuss these results in the context of solid molecular hydrogen at finite pressures.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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