X射线吸收谱中非弹性损耗的多极模型
Many-pole model of inelastic losses in x-ray absorption spectra
摘要：
非弹性损耗对于X射线吸收光谱的定量分析是至关重要的。然而，目前的治疗是半现象学的性质。在这里，第一性原理，多极概括的等离子体激元极模型的非弹性损耗的改进计算。该方法是基于GW近似的自能和实空间多重散射计算的介电函数为一个给定的系统。该模型保留了等离子体激元极模型的效率，并适用于周期性和非周期性材料在很宽的能量范围。同样的多极模型适用于扩展GW计算的准粒子谱函数。这产生多电子激发效应的估计，例如，多体振幅因子$S_0^2$由于固有损耗。说明性的计算进行了比较与其他GW计算的自能，非弹性平均自由程，和实验X射线吸收光谱。
英文摘要：
Inelastic losses are crucial to a quantitative analysis of x-ray absorption spectra. However, current treatments are semi-phenomenological in nature. Here a first-principles, many-pole generalization of the plasmon-pole model is developed for improved calculations of inelastic losses. The method is based on the GW approximation for the self-energy and real space multiple scattering calculations of the dielectric function for a given system. The model retains the efficiency of the plasmon-pole model and is applicable both to periodic and aperiodic materials over a wide energy range. The same many-pole model is applied to extended GW calculations of the quasiparticle spectral function. This yields estimates of multi-electron excitation effects, e.g., the many-body amplitude factor $S_0^2$ due to intrinsic losses. Illustrative calculations are compared with other GW calculations of the self-energy, the inelastic mean free path, and experimental x-ray absorption spectra.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
