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论杂化轨道理论中激发机制的作用

吕东梅1, 吴超2,3   

  1. 1 西安交通大学化学学院, 陕西 西安 710049;
    2 西安交通大学前沿科学技术研究院, 陕西 西安 712046;
    3 西安交通大学前沿科学技术学科交叉中心, 陕西 西安 712046
  • 收稿日期:2025-11-25 录用日期:2026-01-13
  • 通讯作者: 吴超 E-mail:chaowu@xjtu.edu.cn Chao Wu
  • 基金资助:
    感谢西安交通大学2024年研究生教学改革专项(XJG2024068)

On the role of the promotion mechanism in hybrid orbital theory

Dongmei Lu1, Chao Wu2,3   

  1. 1 School of Chemistry, Xi'an Jiaotong University, Xi'an 710049, Shaanxi Province, China;
    2 Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 712046, Shaanxi Province, China;
    3 Interdisciplinary Research Center of Frontier Science and Technology, Xi'an Jiaotong University, Xi'an 712046, Shaanxi Province, China
  • Received:2025-11-25 Accepted:2026-01-13
  • Contact: Chao Wu E-mail:chaowu@xjtu.edu.cn

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摘要： 教科书中对于杂化轨道理论的介绍基本上都采用了“ns电子先激发至np轨道，然后再与其他轨道组合形成杂化轨道”的说法。通过分析该激发机制叙事及其引发的问题，本文认为：(1)杂化轨道理论不需要激发机制；(2)在构建杂化轨道的数学框架内，只需要将参与组合的原子轨道视为一组可以线性组合的基函数，而不需要考虑它们在自由原子中的真实能量差。激发机制只是从能量和价(电子组态)上估算哪些原子轨道可能参与杂化的一个独立模型，它有助于对杂化轨道理论的理解，而非其构成的必需部分。实际上需要通过量子化学计算，才能确知哪些原子轨道参与杂化。

关键词: 杂化轨道理论, 激发, 原子轨道, 杂化

Abstract: The introduction of the hybrid orbital theory in textbooks generally adopts the conventional explanation that “an ns electron is first promoted to an np orbital before combining with other orbitals to form hybrid orbitals”. This paper critically examines this promotion (or excitation) mechanism narrative and addresses the conceptual issues it raises. Our analysis demonstrates that: (1) The hybrid orbital theory fundamentally does not require a promotion mechanism; (2) Within the mathematical framework of orbital hybridization, the participating atomic orbitals need only be treated as a set of linearly combinable basis functions, without consideration of their actual energy differences in free atoms. The promotion mechanism serves merely as an independent model for roughly estimating which atomic orbitals might participate in hybridization based on energy and valence electron configuration considerations. While pedagogically useful for understanding hybrid orbital theory, this mechanism is not an essential component of the theory itself. In practice, determining which orbitals actually participate in hybridization requires quantum chemical calculations.

Key words: Hybrid orbital theory, Promotion, Atomic orbital, Hybridization