Mechanical and Electronic Properties of Iridium Nitride

Based on the structures of known transition metal compounds, the phase stabilities and mechanical properties of iridium nitride （IrN） in nine structures are explored by using ab initio calculations. Tile calculation results show that MnP-structured IrN （MnP IrN） is not only the most energetically stable, but also mechanically and dynamically stable at the ground state. The hardness is estimated to be 12 GPa.     

Spectrum Simulation of Li-Like Aluminium Plasma

X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic recombination, collisional ionization and resonance excitation from the neighbouring ion （Al^9＋ and Al^11＋ ） charge states of the target ion （Al^10＋） are considered in the model. In addition, the contributions of different atomic processes to the x-ray spectrum are analysed. The results show that dielectronic recombination, radiative recombination, collisional ionization and resonance excitation, other than direct collisional excitation, are very important processes.     

Li-like Fe-L壳层等离子体辐射光谱模拟

利用碰撞辐射平衡和离化平衡下的等离子体X-射线发射谱理论,对铁元素L壳层等离子体,在中高能区电子温度范围内,以碰撞激发、离化、辐射复合和双电子复合等动力学过程为主的Fe24 、Fe23 和Fe22 三离子体系X射线谱进行了理论模拟,得到其X射线光谱图,反映出X射线谱辐射波长、辐射强度同电子温度、密度之间的关系,得到了等离子体诊断所关心的电子温度、密度参量的定性关系.     

Li-like镁等离子体X射线光谱模拟

利用碰撞辐射平衡和离化平衡下的等离子体X射线发射谱理论,对镁元素等离子体在中低电子密度、中高电子温度范围内,以碰撞激发、共振激发、离化、辐射复合和双电子复合等动力学过程为主的Mg10 、Mg9 和Mg8 三离子体系X射线谱进行了理论模拟,得到其X射线光谱,反映出X射线辐射谱波长、强度同电子温度之间的关系,得到了等离子体诊断所关心的电子温度的定性关系.     

EuS高压相变及其弹性和热力学性质

采用平面波赝势密度泛函理论,利用第一性原理的方法研究了EuS的晶体结构、高压相变以及弹性性质．计算结果和实验值以及前人利用不同计算模型得到的理论值相吻合．研究了EuS的弹性常数、弹性模量和弹性的各向异性等力学性质随压力变化的趋势．同时研究了泊松比、德拜温度及纵波和横波的弹性波速随压力的变化趋势．基于德拜模型,进而研究了EuS在0～800 K和0～60 GPa下相变前后的热膨胀系数、热熔、Grüneisen参数等热力学性质．     

EuS高压相变发其弹性和热力学性质

采用平面波赝势密度泛函理论,利用第一性原理的方法研究了EuS的晶体结构、高压相变以及弹性性质．计算结果和实验值以及前人利用不同计算模型得到的理论值相吻合．研究了EuS的弹性常数、弹性模量和弹性的各向异性等力学性质随压力变化的趋势．同时研究了泊松比、德拜温度及纵波和横波的弹性波速随压力的变化趋势．基于德拜模型,进而研究了EuS在0-800K和0-60GPa下相变前后的热膨胀系数、热熔、Gruneisen参数等热力学性质．     

电子与Mg5+碰撞激发的碰撞强度研究

采用多通道R-matrix程序计算了电子与Mg5 离子碰撞激发的碰撞强度.所有的跃迁均限定在主量子数为2的态之间.计算结果与用相对论扭曲波方法得到的结果进行了比较,R-matrix方法所得的结果更好.文中列出了部分光允许跃迁的数据,可以看出,R-matrix方法更适合计算低能碰撞.     

Experimental observation of the linewidth narrowing of electromagnetically induced transparency resonance

Many theoretical and experimental works show that the effect of electromagnetically induced transparency (EIT) is becoming an important tool for implementation of quantum information science. Nevertheless, EIT is a fragile quantum interference effect; the ideal trans- parency is achieved at exactly the two-photon resonance condition, i.e., when the frequency detuning of two pho- tons is zero. If the frequency detuning of two photons is slightly nonzero, the interference is destroyed and the …