Yang L H, Gong J M, Sulyok A, Menyhárd M, Sáfrán G, Tőkési K, Da B, Ding Z J
Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
Research and Services Division of Materials Data and Integrated System, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Phys Chem Chem Phys. 2021 Nov 17;23(44):25335-25346. doi: 10.1039/d1cp02447g.
We present the combined experimental and theoretical investigations of the optical properties of amorphous carbon. The reflection electron energy loss spectra (REELS) spectra of carbon were measured using a cylindrical mirror analyzer under ultrahigh vacuum conditions at primary electron energies of 750, 1000 and 1300 eV. The energy loss function and thereby the refractive index and the extinction coefficient were determined from these REELS spectra in a wide loss energy range of 2-200 eV by applying our reverse Monte Carlo method. The high accuracy of the obtained optical constants is justified with the ps- and f-sum rules. We found that our present optical constants of amorphous carbon fulfill the sum rules with the highest accuracy compared with the previously published data. Therefore, we highly recommend to replace the previous data with the present ones for practical applications. Moreover, we present the atomic scattering factors of amorphous carbon obtained from the dielectric function to predict its optical constants at a given density.
我们展示了对非晶碳光学性质的联合实验和理论研究。在超高真空条件下，使用圆柱镜分析仪在750、1000和1300 eV的一次电子能量下测量了碳的反射电子能量损失谱（REELS）。通过应用我们的反向蒙特卡罗方法，在2 - 200 eV的宽损失能量范围内，从这些REELS谱确定了能量损失函数，进而确定了折射率和消光系数。通过ps和f和规则证明了所获得光学常数的高精度。我们发现，与先前发表的数据相比，我们目前的非晶碳光学常数以最高精度满足和规则。因此，我们强烈建议在实际应用中用当前数据取代先前的数据。此外，我们展示了从介电函数获得的非晶碳的原子散射因子，以预测其在给定密度下的光学常数。
