不需制备样品与获得期望强度的红外单光束谱

摘要

In order to compensate for solvent bands and other background effects,a successful infrared (IR) spectral measurement requires a quality single-beam background spectrum with a desired intensity.Usually,it is extremely difficult to bring a background component to the desired intensity in practice.In order to achieve this important but difficult goal,a hybrid single-beam spectrum α=αb1+(1-α)b2 is introduced as the combination of two single-beam spectra b1 and b2 from the same sample but with different pathlengths (b1 and b2),where α (0≤α≤1) is the component factor.Obviously,the intensity of the hybrid spectrum α can be controlled easily to the desired point by simply choosing an appropriate component factor.Under appropriate conditions,the hybrid spectrum α is very nearly identical to the single-beam spectrum obtained from the real sample with the pathlength of b2-αb2+αb1 and the minor spectral distortion of α can be dismissed.As a result,the single-beam spectrum of a real sample b with a pathlength of b2-αb2+αb1 can be represented by α and the real sample does not need to be prepared.Experimentally,the hybrid single-beam spectrum provides a very simple,robust and efficient method to overcome the interference from background samples of IR measurements and shows valuable potential in applications of this field.%为扣除溶剂或其他背景组分的干扰,测量红外光谱时常常需要获得期望强度的高质量背景单光束谱.通常,实验上获得期望强度的背景谱是极其困难的.为实现这一重要且十分困难的目标,引进了杂化单光束谱的概念.同一溶液但不同厚度的b1和b2的两样品的单光束谱分别为b1和b2,则定义它们的线性组合α=αb1+(1-α)b2为杂化单光束谱,其中α(0≤α≤1)称为组分因子.调整组分因子α数值,就可以精确调控杂化谱的强度.在合适的条件下,杂化谱α与厚度为b2-αb2+αb1的真实样品的光谱高度类似,即b2-αb2+αb1≈α.因此,不用制备厚度为b2-αb2+αb1的样品,其单光束谱可以用α来替代.随着α变化,可以得到不同的α,厚度在b1和b2间的真实样品的单光束谱都可用相应的α来替代.实验结果证实,杂化谱提供了一种简单和易操作的扣除背景干扰的高效方法.