Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
J Chem Phys. 2013 Feb 21;138(7):074308. doi: 10.1063/1.4790862.
A formula for the cross section of radiative association where no electronic transitions take place is derived and tested for diatomic molecules. The approach is based on classical mechanics and therefore it is valid for direct, i.e., non-resonant, radiative association. For the formation of carbon monoxide (CO) and the cyano radical (CN), in the X1Σ+ and A1Π states, respectively, the treatment reproduces the baselines of the cross sections obtained using quantum mechanical perturbation theory. The method overestimates the formation cross section of potassium sodide (NaK) by about 8%. For the lower mass diatoms hydrogen fluoride (HF) and deuterium hydride (HD), the formula overestimates the cross sections by 12% and 60%, respectively. The formula can be used alone for estimates of radiative association rate constants, or in combination with Breit-Wigner theory to include resonance contributions.
推导出了一个不发生电子跃迁的辐射缔合截面公式，并对双原子分子进行了测试。该方法基于经典力学，因此适用于直接的，即非共振的辐射缔合。对于一氧化碳（CO）和氰基自由基（CN）分别在 X1Σ+和 A1Π 态的形成，该处理方法再现了使用量子力学微扰理论获得的截面的基线。该方法高估了钾钠化物（NaK）形成截面约 8%。对于质量较低的双原子分子氟化氢（HF）和氘化氢（HD），该公式分别高估了截面 12%和 60%。该公式可单独用于估计辐射缔合速率常数，或与 Breit-Wigner 理论结合以包含共振贡献。
