High-Pressure Science and Engineering Center (HiPSEC) and Department of Physics, University of Nevada Las Vegas (UNLV), Las Vegas, Nevada 89154-4002, United States.
J Phys Chem A. 2013 Mar 21;117(11):2302-6. doi: 10.1021/jp4008812. Epub 2013 Mar 12.
We report the first measurements of the X-ray induced decomposition of KClO3 as a function of energy in two experiments. KClO3 was pressurized to 3.5 GPa and irradiated with monochromatic synchrotron X-rays ranging in energy from 15 to 35 keV in 5 keV increments. A systematic increase in the decomposition rate as the energy was decreased was observed, which agrees with the 1/E(3) trend for the photoelectric process, except at the lowest energy studied. A second experiment was performed to access lower energies (10 and 12 keV) using a beryllium gasket; suggesting an apparent resonance near 15 keV or 0.83 Ǻ maximizing the chemical decomposition rate. A third experiment was performed using KIO3 to ascertain the anionic dependence of the decomposition rate, which was observed to be far slower than in KClO3, suggesting that the O-O distance is the critical factor in chemical reactions. These results will be important for more efficiently initiating chemical decomposition in materials using selected X-ray wavelengths that maximize decomposition to aid useful hard X-ray-induced chemistry and contribute understanding of the mechanism of X-ray-induced decomposition of the chlorates.
我们报告了首次测量 KClO3 在两种实验中随能量变化的 X 射线诱导分解。KClO3 在 3.5 GPa 下加压，并以 5 keV 的增量用能量从 15 到 35 keV 的单色同步加速器 X 射线辐照。观察到随着能量降低分解速率呈系统性增加，这与光电过程的 1/E(3)趋势一致，除了在研究的最低能量下。进行了第二次实验以使用铍垫圈访问较低的能量（10 和 12 keV）；表明在 15 keV 或 0.83 Ǻ 附近存在明显的共振，最大限度地提高了化学分解速率。进行了第三次实验，使用 KIO3 来确定分解速率的阴离子依赖性，发现其远低于 KClO3，这表明 O-O 距离是化学反应的关键因素。这些结果对于使用选定的 X 射线波长更有效地引发材料中的化学分解将非常重要，这些波长可最大程度地促进分解，以辅助有用的硬 X 射线诱导化学，并有助于理解氯酸盐的 X 射线诱导分解机制。
