双语化学辞典Chem Lexicon
高中Senior high 原子结构与量子化起源 Atomic structure & the origins of quantisation

玻尔模型的能级Energy levels of the Bohr model

\[E_n = -\frac{m_e e^4}{8\varepsilon_0^2h^2}\cdot\frac{Z^2}{n^2} = -13.6\ \mathrm{eV}\cdot\frac{Z^2}{n^2},\qquad r_n = \frac{n^2a_0}{Z}\]

含义Meaning

玻尔(1913)假设电子在定态圆轨道上运动、角动量量子化 \(m_evr = n\hbar\),得到氢原子能级,完美解释了氢光谱。

Bohr (1913) assumed stationary circular orbits with quantised angular momentum \(m_evr = n\hbar\), deriving hydrogen’s levels and explaining its spectrum.

符号说明Symbols

符号Symbol含义 Meaning单位 Unit
\(n\)主量子数principal quantum number1
\(Z\)核电荷数nuclear charge1
\(a_0\)玻尔半径 52.9 pmBohr radiusm

推导Derivation

  1. 库仑力提供向心力:\(\frac{Ze^2}{4\pi\varepsilon_0r^2} = \frac{m_ev^2}{r}\)。

    Coulomb force provides the centripetal force.

  2. 角动量量子化 \(m_evr = n\hbar\),联立解出 \(r_n = \frac{4\pi\varepsilon_0\hbar^2n^2}{m_eZe^2} = n^2a_0/Z\)。

    With \(m_evr = n\hbar\), \(r_n = n^2a_0/Z\).

  3. 总能量 \(E = \tfrac12m_ev^2 - \frac{Ze^2}{4\pi\varepsilon_0r} = -\frac{Ze^2}{8\pi\varepsilon_0r}\),代入 r_n 得 E_n。

    Total energy \(-Ze^2/(8\pi\varepsilon_0r)\) gives E_n.

适用条件与局限Assumptions & limitations

  • 只适用于单电子体系(H、He⁺、Li²⁺);不能解释多电子原子、谱线强度与精细结构,“轨道”概念被量子力学的轨道(波函数)取代。

    One-electron systems only; fails for intensities, fine structure and many-electron atoms. Orbits are replaced by orbitals in quantum mechanics.

  • 结果与薛定谔方程的能级相同(属巧合式的正确)。

    The energies coincide with the Schrödinger result.

例题Worked example

氢原子电离能 = E_∞ − E₁ = 13.6 eV = 1312 kJ/mol;He⁺ 为 54.4 eV。

Hydrogen ionisation energy 13.6 eV (1312 kJ/mol); He⁺ 54.4 eV.