An accurate potential energy model, explicitly designed for studying scattering and treating the spin–orbit and nonadiabatic couplings on an equal footing, is proposed for the S + Ar system. The model is based on the Effective Relativistic Coupling by Asymptotic Representation (ERCAR) approach, building the geometry dependence of the spin–orbit interaction via a diabatisation scheme. The resulting full diabatic model is used in close-coupling calculations to compute inelastic scattering cross sections for de-excitation from the S(¹D₂) fine structure level into the ³P multiplet. The energy grid is tuned to resolve the many resonances present and to guarantee converged thermal rates from 1 to 300 K. At temperatures above 100 K, the computed thermal rate coefficients for quenching of S(¹D₂) are in good agreement with results from an earlier experimental and theoretical study. The branching ratio at 296 K for de-excitation into the S(³P₀) level agrees well with the value obtained by a different experiment. A discrepancy however remains between theory and experiment at lower temperatures. This is discussed in light of the interference mechanisms at play during this quenching process.

中文翻译：

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氩碰撞诱导的硫的电子淬火


为 S + Ar 系统提出了一个精确的势能模型，该模型专门用于研究散射和平等地处理自旋-轨道和非绝热耦合。该模型基于渐近表示的有效相对论耦合 （ERCAR） 方法，通过绝热化方案构建自旋-轨道相互作用的几何依赖性。所得的全非绝热模型用于紧耦合计算，以计算非弹性散射截面，以便从 S（¹D₂） 精细结构水平去激发到 ³P 多重态。对能源网进行了调整，以解决存在的许多共振，并保证从 1 到 300 K 的收敛热速率。在高于 100 K 的温度下，计算出的 S（¹D₂） 淬火热速率系数与早期实验和理论研究的结果非常一致。在 296 K 时去激发到 S（³P₀） 水平的支化比与通过不同实验获得的值非常吻合。然而，在较低温度下，理论和实验之间仍然存在差异。根据此淬灭过程中起作用的干扰机制对此进行了讨论。