On the J-Shift Approximation in Quantum Reaction Dynamics
On the J-Shift Approximation in Quantum Reaction Dynamics
复制标题
量子反应动力学中的 J-Shift 近似
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
Hiroki Nakamura
中科院分区：
文献类型：
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作者：
Katsuyuki Nobusada† and;Hiroki Nakamura
以O（3 P）+ HCl →OH + Cl反应为例，数值研究了J位移或能移近似的有效性.仅仅基于J（总角动量量子数）= 0的近似，即通常的J位移近似，不能很好地再现反应动力学，尤其是当初始转动量子数很高时.对于特定的初始振转态的反应速率常数被高估或低估取决于初始状态和温度。与热速率常数的精确结果的良好一致似乎是相当偶然的，因为这些高估和低估的取消。本文提出了一种扩展的J-位移近似，它可以精确地计算到J = ji，|Ω|当ji ≤ Ωmax时，≤ Ωmax，或当ji > Ωmax时，达到J = Ωmax，其中Ωmax是体固定投影量子数Ω的绝对值的最大值，该绝对值对量子数的贡献是显著的。
The validity of the J-shift or the energy-shift approximation is investigated numerically by taking the reaction O(3P) + HCl →OH + Cl as an example. The approximation based only on the results of J (total angular momentum quantum number) = 0, which is the ordinary J-shift approximation, cannot reproduce the exact reaction dynamics well, especially when the initial rotational quantum number is high. The reaction rate constants for specified initial rovibrational states are over- or underestimated depending on the initial state and temperature. The good agreement with the accurate result of the thermal rate constant seems to be rather accidental because of the cancellations of these over- and underestimates. An extended J-shift approximation is proposed, in which accurate calculations should be carried out up to J = ji with |Ω| ≤ Ωmax when ji ≤ Ωmax, or up to J = Ωmax when ji > Ωmax, where Ωmax is the maximum of the absolute values of the body-fixed projection quantum number Ω that give noticeable contribut...