National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Central 3, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8563, Japan.
Anal Sci. 2021 Nov 10;37(11):1533-1539. doi: 10.2116/analsci.21P054. Epub 2021 Apr 23.
The Raman shift is one of the most important parameters in Raman spectroscopy, and is calculated from the difference in the wavenumbers for excitation and for Raman scattering. Because the observed shifts are strongly dependent on the spectrometer and the measurement conditions, physically and chemically stable reference materials for Raman-shift validation are required. We reliably estimated the Raman shift and evaluated its uncertainty for peaks of a 4-mm-thick, 25-mm-diameter polystyrene disc by using a HeNe laser and Raman-scattered light calibrated with Ne/Ar emission lines. We considered uncertainties originating from the fitting, repeatability, and reproducibility of both the Ne/Ar emission lines and the Rayleigh/Raman-scattered lights, as well as the wavenumber of the unstabilised HeNe laser, and pixel and spectral resolutions. We also considered uncertainty originating from inhomogeneity among and within discs, as well as their long-term stability. The obtained Raman shifts of 11 peaks (reference values) were comparable to those described in ASTM E1840 with expanded uncertainty at 1.1 or 1.2 cm (k = 2, coverage factor).
拉曼位移是拉曼光谱学中最重要的参数之一，它是通过激发和拉曼散射的波数差计算得出的。由于观察到的位移强烈依赖于光谱仪和测量条件，因此需要物理和化学稳定的拉曼位移验证参考物质。我们使用氦氖激光和用氖/氩发射线校准的拉曼散射光可靠地估计了一个 4 毫米厚、25 毫米直径的聚苯乙烯圆盘的拉曼位移，并评估了其不确定度。我们考虑了源自拟合、重复性和再现性的不确定度，包括未稳定的氦氖激光的波数、像素和光谱分辨率，以及来自圆盘之间和内部的不均匀性及其长期稳定性的不确定度。11 个峰（参考值）的获得的拉曼位移与 ASTM E1840 中描述的拉曼位移相当，扩展不确定度为 1.1 或 1.2 cm（k = 2，覆盖因子）。
