First-principles calculations of K-shell X-ray absorption spectra for warm dense nitrogen
First-principles calculations of K-shell X-ray absorption spectra for warm dense nitrogen
复制标题
暖密氮K壳层X射线吸收光谱的第一性原理计算
DOI：
10.1063/1.4951022
复制
发表时间：
2016
影响因子：
2.2
通讯作者：
Zhang Ping
中科院分区：
文献类型：
--
作者：
Li Zi;Zhang Shen;Wang Cong;Kang Wei;Zhang Ping
X射线吸收光谱是探测热致密物质原子结构的有力工具。在这里，我们进行第一性原理分子动力学和X-射线吸收光谱计算暖致密氮沿着的Hugoniot曲线。从分子动力学轨迹，详细的原子结构进行检查，为每一个特定的条件。计算了K壳层X射线吸收谱，讨论了K壳层X射线吸收谱沿Hugoniot曲线沿着随温度和压力的变化。温暖的致密氮系统可能包含孤立的氮原子、N2分子和氮团簇，由于它们的电子态密度不同，它们对总X射线谱的贡献也不同。X射线谱沿着Hugoniot曲线的变化是由温度和压力引起的氮结构的不同引起的。指出了不同温度条件下的X射线能谱特征，为今后的X射线研究提供了有用的数据。
X-ray absorption spectrum is a powerful tool for atomic structure detection on warm dense matter. Here, we perform first-principles molecular dynamics and X-ray absorption spectrum calculations on warm dense nitrogen along a Hugoniot curve. From the molecular dynamics trajectory, the detailed atomic structures are examined for each thermodynamical condition. The K-shell X-ray absorption spectrum is calculated, and its changes with temperature and pressure along the Hugoniot curve are discussed. The warm dense nitrogen systems may contain isolated nitrogen atoms, N2 molecules, and nitrogen clusters, which show quite different contributions to the total X-ray spectrum due to their different electron density of states. The changes of X-ray spectrum along the Hugoniot curve are caused by the different nitrogen structures induced by the temperature and the pressure. Some clear signatures on X-ray spectrum for different thermodynamical conditions are pointed out, which may provide useful data for future X-ray e...