A study of the reactions of Al+ ions with O3, N2, O2, CO2 and H2O: influence on Al+ chemistry in planetary ionospheres.
A study of the reactions of Al+ ions with O3, N2, O2, CO2 and H2O: influence on Al+ chemistry in planetary ionospheres.
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DOI：
10.1039/c8cp07572g
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
Shane M. Daly;D. Bones;J. Plane
中科院分区：
文献类型：
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作者：
Shane M. Daly;D. Bones;J. Plane
研究了Al+(31S)与O_3、O_2、N_2、CO_2和H_2O的反应，用532 nm脉冲激光烧蚀快流管中的铝靶，用质谱仪检测Al~+和AlO~+。Al+与O_3反应的速率系数为k(293K)=(1·4±0·1)×10~(-9)cm~3分子~(-1)·S~(-1)，反应以离子偶极增强朗之万俘获频率进行，预测的T~(-0.16)依赖于此。对于复合反应，将电子结构理论计算与莱斯-拉姆斯佩格-卡塞尔-马库斯理论相结合，将测量的速率系数外推到行星电离层的温度和压力条件。在温度T=120K-400K和浴气(在CM6分子-2 S-1中，180K时的不确定度±σ)下，得到了如下的低压极限速率系数：log10(k，Al++N_2)=-27.9739+0.05036 log10(T)-0.60987(log10(T))2，σ=12%，log10(k，Al++CO_2)=-33.6387+7.0522 log10(T)-2.1467(log10(T))2，σ=13%；Log10(k，Al++H2O)=-24.7835+0.018833 log10(T)-0.6436(log10(T))2，σ=27%。没有观察到Al++O2反应，与D°(Al+-O2)键强度仅为12kJ mol-1一致。还研究了AlO+的两个反应：K(AlO++O_3,293K)=(1.3±0.6)×10~(-9)cm~3分子~(-1)S~(-1)，其中(63±9)%生成Al~+，而不是OAlO~+；k(AlO~++H_2O，293K)=(9±4)×10~(-10)cm~3分子~(-1)S~(-1)。然后讨论了地球和火星电离层中Al+的化学。
The reactions between Al+(31S) and O3, O2, N2, CO2 and H2O were studied using the pulsed laser ablation at 532 nm of an aluminium metal target in a fast flow tube, with mass spectrometric detection of Al+ and AlO+. The rate coefficient for the reaction of Al+ with O3 is k(293 K) = (1.4 ± 0.1) × 10-9 cm3 molecule-1 s-1; the reaction proceeds at the ion-dipole enhanced Langevin capture frequency with a predicted T-0.16 dependence. For the recombination reactions, electronic structure theory calculations were combined with Rice-Ramsperger-Kassel-Markus theory to extrapolate the measured rate coefficients to the temperature and pressure conditions of planetary ionospheres. The following low-pressure limiting rate coefficients were obtained for T = 120-400 K and He bath gas (in cm6 molecule-2 s-1, uncertainty ±σ at 180 K): log10(k, Al+ + N2) = -27.9739 + 0.05036 log10(T) - 0.60987(log10(T))2, σ = 12%; log10(k, Al+ + CO2) = -33.6387 + 7.0522 log10(T) - 2.1467(log10(T))2, σ =13%; log10(k, Al+ + H2O) = -24.7835 + 0.018833 log10(T) - 0.6436(log10(T))2, σ = 27%. The Al+ + O2 reaction was not observed, consistent with a D°(Al+-O2) bond strength of only 12 kJ mol-1. Two reactions of AlO+ were also studied: k(AlO+ + O3, 293 K) = (1.3 ± 0.6) × 10-9 cm3 molecule-1 s-1, with (63 ± 9)% forming Al+ as opposed to OAlO+; and k(AlO+ + H2O, 293 K) = (9 ± 4) × 10-10 cm3 molecule-1 s-1. The chemistry of Al+ in the ionospheres of Earth and Mars is then discussed.