1.1本指南旨在使用低压弧光灯发射线或校准的方解石拉曼波段对拉曼光谱仪的光谱分辨率进行常规测试和评估。 1.2以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3由于使用激光存在重大危险，因此应结合本实践遵守ANSI Z136.1。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 4.1如果要在系统之间传输光谱，如果要使用各种采样附件，或者如果光谱仪可以在多个激光激发波长下工作，则评估拉曼光谱仪的光谱仪分辨率和仪器线型（ILS）功能对于在各种光谱仪系统之间获得的光谱的相互可比性非常重要。 4.2低压放电灯（钢笔灯，如汞、氩或氖）提供了一种低成本的方法，可以在扩展的波长范围内为各种拉曼系统提供分辨率和波数校准。 4.3然而，为此目的使用发射线有几个缺点。 4.3.1首先，可能很难将灯具与样品位置正确对齐，从而导致线变形，尤其是当光谱仪的入口狭缝填充不足或未对称照明时。 4.3.2其次，许多发射源具有高密度光谱，这可能使分辨率和波数校准复杂化，尤其是在低分辨率系统上。 4.3.3第三，拉曼光谱特征的谱线展宽的一个重要因素可能是激发激光线宽本身，这是使用钢笔灯评估光谱仪分辨率时未评估的一个组成部分。 4.3.4替代方法是使用拉曼活性化合物代替发射源。 该化合物应具有化学惰性、稳定性和安全性，理想情况下应提供均匀分布在0 cm范围内的拉曼光谱 -1 （拉曼位移）到C-H拉伸区域3000 cm -1 及以上。这些拉曼带的带宽应该不同。 4.4迄今为止，尚未确定此类理想样品；然而，四氯化碳（见规程E1683）和萘（见指南E1840）之前已用于分辨率和拉曼频移校准。 4.5本指南将讨论使用方解石来评估拉曼系统的分辨率。方解石是一种天然矿物，具有拉曼分辨率标准所需的许多光学特性，价格低廉、安全且易于获得。 4.6色散拉曼光谱仪的光谱带宽主要由光谱仪的焦距、光栅的色散和狭缝宽度决定。野外便携式系统通常使用固定的狭缝和光栅，因此使用固定的光谱带宽，而在许多实验室系统中，狭缝宽度和光栅是可变的。 通过改变干涉仪的光程差，傅里叶变换（FT）-拉曼系统的光谱带宽是连续可变的，并且能够获得比大多数实际色散系统低得多的光谱带宽。因此，在FT-Raman系统上获得的窄带拉曼数据可用于确定色散拉曼系统的分辨率。1085 cm半高全宽（FWHH）的校准曲线 -1 方解石带是光谱分辨率的函数。 4. 在测试色散仪器上测量该方解石带可以估计光谱仪分辨率。 4.7本指南将描述方解石灯和笔灯用于评估在785 nm激光波长下运行的色散（基于光栅）拉曼系统的拉曼光谱仪分辨率。

1.1 This guide is designed for routine testing and assessment of the spectral resolution of Raman spectrometers using either a low-pressure arc lamp emission lines or a calibrated Raman band of calcite. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 Because of the significant dangers associated with the use of lasers, ANSI Z136.1 shall be followed in conjunction with this practice. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 4.1 Assessment of the spectrometer resolution and instrument line shape (ILS) function of a Raman spectrometer is important for intercomparability of spectra obtained among widely varying spectrometer systems, if spectra are to be transferred among systems, if various sampling accessories are to be used, or if the spectrometer can be operated at more than one laser excitation wavelength. 4.2 Low-pressure discharge lamps (pen lamps such as mercury, argon, or neon) provide a low-cost means to provide both resolution and wave number calibration for a variety of Raman systems over an extended wavelength range. 4.3 There are several disadvantages in the use of emission lines for this purpose, however. 4.3.1 First, it may be difficult to align the lamps properly with the sample position leading to distortion of the line, especially if the entrance slit of the spectrometer is underfilled or not symmetrically illuminated. 4.3.2 Second, many of the emission sources have highly dense spectra that may complicate both resolution and wave number calibration, especially on low-resolution systems. 4.3.3 Third, a significant contributor to line broadening of Raman spectral features may be the excitation laser line width itself, a component that is not assessed when evaluating the spectrometer resolution with pen lamps. 4.3.4 An alternative would use a Raman active compound in place of the emission source. This compound should be chemically inert, stable, and safe and ideally should provide Raman bands that are evenly distributed from 0 cm -1 (Raman shift) to the C-H stretching region 3000 cm -1 and above. These Raman bands should be of varying bandwidth. 4.4 To date, no such ideal sample has been identified; however carbon tetrachloride (see Practice E1683) and naphthalene (see Guide E1840) have been used previously for both resolution and Raman shift calibration. 4.5 The use of calcite to assess the resolution of a Raman system will be addressed in this guide. Calcite is a naturally occurring mineral that possesses many of the desired optical properties for a Raman resolution standard and is inexpensive, safe, and readily available. 4.6 The spectral bandwidth of dispersive Raman spectrometers is determined primarily by the focal length of the spectrometer, the dispersion of the grating, and the slit width. Field portable systems typically operate with fixed slits and gratings and thus operate with a fixed spectral bandwidth, while in many laboratory systems the slit widths and gratings are variable. The spectral bandwidth of Fourier-Transform (FT)-Raman systems is continuously variable by altering the optical path difference of the interferometer and furthermore is capable of obtaining much lower spectral bandwidth than most practical dispersive systems. Therefore, data obtained of a narrow Raman band on a FT-Raman system can be used to determine the resolution of a dispersive Raman system. A calibration curve of the full width at half height (FWHH) for the 1085-cm -1 band of calcite as a function of spectral resolution has been reported for this purpose. 4 Measurement of this calcite band on a test dispersive instrument enables an estimation of the spectrometer resolution. 4.7 This guide will describe the use of calcite and pen lamps for the evaluation of Raman spectrometer resolution for dispersive (grating based) Raman systems operating with a 785-nm laser wavelength.