Wakisaka Yuki, Hu Bing, Kido Daiki, Al Rashid Md Harun, Chen Wenhan, Dong Kaiyue, Wada Takahiro, Bharate Bapurao, Yuan Quiyi, Mukai Shingo, Takeichi Yasuo, Takakusagi Satoru, Asakura Kiyotaka
Institute for Catalysis, Hokkaido University, Kita 21-10, Sapporo, Hokkaido 001-0021, Japan.
Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
J Synchrotron Radiat. 2020 Nov 1;27(Pt 6):1618-1625. doi: 10.1107/S1600577520011170. Epub 2020 Oct 16.
A bent crystal Laue analyser (BCLA) is an X-ray energy analyser used for fluorescence X-ray absorption fine-structure (XAFS) spectroscopy to separate the fluorescence X-ray emission line of a target atom from the elastic scattering X-rays and other fluorescence emission lines. Here, the feasibility of the BCLA for total reflection fluorescence XAFS (TRF-XAFS), which has a long X-ray footprint on the substrate surface owing to grazing incidence, was tested. The focal line of the BCLA was adjusted on the X-ray footprint and the XAFS signal for one monolayer of Pt deposited on a 60 nm Au film with high sensitivity was obtained. Although range-extended XAFS was expected by the rejection of Au fluorescence arising from the Au substrate, a small glitch was found in the Au L edge because of the sudden change of the complex refraction index of the Au substrate at the Au edge. This abnormal spectrum feature can be removed by reflectivity correction using Au foil absorption data. BCLA combined with TRF-XAFS spectroscopy (BCLA + TRF-XAFS) is a new technique for the in situ surface analysis of highly dispersed systems even in the presence of a liquid overlayer.
弯曲晶体劳厄分析仪（BCLA）是一种X射线能量分析仪，用于荧光X射线吸收精细结构（XAFS）光谱分析，以将目标原子的荧光X射线发射线与弹性散射X射线及其他荧光发射线分离。在此，对BCLA用于全反射荧光XAFS（TRF-XAFS）的可行性进行了测试，由于掠入射，TRF-XAFS在衬底表面具有较长的X射线足迹。将BCLA的焦线调整到X射线足迹上，并以高灵敏度获得了沉积在60 nm金膜上的单层铂的XAFS信号。尽管通过排除金衬底产生的金荧光有望实现扩展范围的XAFS，但由于金衬底在金边缘处复折射率的突然变化，在金L边缘发现了一个小故障。这种异常的光谱特征可以通过使用金箔吸收数据进行反射率校正来消除。BCLA与TRF-XAFS光谱相结合（BCLA + TRF-XAFS）是一种即使在存在液体覆盖层的情况下也能对高度分散体系进行原位表面分析的新技术。
