Experimental study of the removal of excited state phosphorus atoms by H2O and H2: implications for the formation of PO in stellar winds
Experimental study of the removal of excited state phosphorus atoms by H2O and H2: implications for the formation of PO in stellar winds
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H2O和H2去除激发态磷原子的实验研究：对恒星风中PO形成的影响
DOI：
10.1093/mnras/stac1684
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发表时间：
2022
影响因子：
4.8
通讯作者：
Douglas K
中科院分区：
文献类型：
--
作者：
Douglas K
通过 PCl3 在 248 nm 处的脉冲激光光解，结合激光诱导荧光检测 P(2D)、P(2P) 和 PO，研究了原子磷 P(2D) 和 P(2P) 的低位亚稳态与 H2O 和 H2 的反应。测量了 291 至 740 K 之间的速率系数，以及由 P(2D 或 2P) + H2O 生产 PO 的产率为 (35 ± 15) %。 H2 与两种激发 P 态的反应相对有效；物理（即碰撞）猝灭，而不是产生 PH + H 的化学反应，被证明是更可能的途径。然后，结合电子结构理论计算和复杂势能表面上发生的反应的主方程处理，开发了一个全面的磷化学网络。由此产生的模型表明，在富氧条件下，MIRA 变星 AGB 星的两个恒星半径内的高温下，基态 P(4S) 碰撞激发为 P(2D)，然后与 H2O 反应，是产生 PO 的重要途径（除了 P(4S) 和 OH 之间的反应之外）。该模型还表明，稳定（非脉动）流出中的 PN 分数丰度被低估了约 2 个数量级。然而，在高于 4000 K 的温度下 N2 发生充分热解离的冲击条件下，产生的 N 原子将大部分 PO 转化为 PN。
The reactions of the low-lying metastable states of atomic phosphorus, P(2D) and P(2P), with H2O and H2were studied by the pulsed laser photolysis at 248 nm of PCl3, combined with laser-induced fluorescence detection of P(2D), P(2P), and PO. Rate coefficients between 291 and 740 K were measured, along with a yield for the production of PO from P(2D or2P) + H2O of (35 ± 15) %. H2reacts with both excited P states relatively efficiently; physical (i.e. collisional) quenching, rather than chemical reaction to produced PH + H, is shown to be the more likely pathway. A comprehensive phosphorus chemistry network is then developed using a combination of electronic structure theory calculations and a Master Equation treatment of reactions taking place over complex potential energy surfaces. The resulting model shows that at the high temperatures within two stellar radii of a MIRA variable AGB star in oxygen-rich conditions, collisional excitation of ground-state P(4S) to P(2D), followed by reaction with H2O, is a significant pathway for producing PO (in addition to the reaction between P(4S) and OH). The model also demonstrates that the PN fractional abundance in a steady (non-pulsating) outflow is underpredicted by about 2 orders of magnitude. However, under shocked conditions where sufficient thermal dissociation of N2occurs at temperatures above 4000 K, the resulting N atoms convert a substantial fraction of PO into PN.
宇宙化学纽带：从大爆炸到行星形成的化学
DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
D. Williams;T. Hartquist
通讯作者：
T. Hartquist