Phosphorus is critical to humans on many fronts, yet we do not have a mechanistic understanding of some of its most basic transformations and reactions─namely the oligomerization of white phosphorus to red. With heat or under ultraviolet (UV) exposure, it has been experimentally demonstrated that white phosphorus dissociates into diphosphorus units which readily form red phosphorus. However, the mechanism of this process is unknown. The ab initio nanoreactor approach was used to explore the potential energy surface of phosphorus clusters. Density functional theory and metadynamics simulations were used to characterize potential reaction pathways. A mechanism for oligomerization is proposed to take place via diphosphorus additions at π-bonds and weak σ-bonds through three membered ring intermediates. Downhill paths through P₆ and P₈ clusters eventually result in P₁₀ clusters that can oligomerize into red phosphorus chains. The initial, rate limiting step for this process has an energy barrier of 24.2 kcal/mol.

中文翻译：

---

Two P、Ten P、White P、Red P：使用 Ab Initio 纳米反应器从二磷低聚化红磷的机理探索


磷在许多方面对人类至关重要，但我们对其一些最基本的转化和反应（即白磷向红色的寡聚化）没有机械理解。在高温或紫外线 （UV） 照射下，实验证明白磷会解离成二磷单元，这些单元很容易形成红磷。然而，这个过程的机制尚不清楚。采用 ab initio 纳米反应器方法探索磷簇的势能表面。密度泛函理论和元动力学模拟用于表征潜在的反应途径。提出了一种寡聚化机制，通过在三个成员环中间体的 π 键和弱 σ 键处添加二磷来实现。通过 P₆ 和 P₈ 簇的下坡路径最终导致 P₁₀ 簇，这些簇可以低聚化成红磷链。此过程的初始限速步骤具有 24.2 kcal/mol 的能垒。