Liu Xiao-dong, Hou Lan-tian
Institute of Infrared Optical Fibers and Sensors, Yanshan University, Qinhuangdao 066004, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2002 Oct;22(5):770-3.
In the spectroscopic experiments, additionally large extinction caused by the scattering in the vicinity of inherent absorption peaks of the measured sample granules can lead to a deviation of measured absorption peak from the corresponding inherent one, then an incorrect spectrum appears. This is just the Christiansen effect that we must take cares to avoid as much as possible. One of the measures we take is to use a small amount of sample material (less than 2%) when we make the pellets, for example KBr is the matrix. In an experiment, when a large (not small as usual) amount of alpha-SiC powder is dispersed into KBr powder, the resulted pellet has an infrared transmission spectrum with a sharp peak at the position of 1,052.33 cm-1. We find that this new phenomenon is very interesting, and looks contrary to the usual Christiansen effect, but can be explained with Lorentz dispersion model accurately together, so we call it reverse-Christiansen effect. Exactly at this frequency, the refractive indices of these two materials are equal, and absorption coefficients are very small. Also, it is very useful for making a new type of band-pass filter or determining the refractive indices of some materials correctly, etc.
在光谱实验中，另外，被测样品颗粒固有吸收峰附近的散射所引起的较大消光会导致测量的吸收峰偏离相应的固有吸收峰，进而出现不正确的光谱。这正是我们必须尽可能小心避免的克里斯琴森效应。我们采取的措施之一是在制作压片时使用少量样品材料（小于2%），例如以溴化钾作为基质。在一次实验中，当大量（不像往常那样少量）的α-碳化硅粉末分散到溴化钾粉末中时，所得压片的红外透射光谱在1052.33 cm-1处有一个尖锐峰。我们发现这种新现象非常有趣，看起来与通常的克里斯琴森效应相反，但可以用洛伦兹色散模型一起准确解释，所以我们称之为反克里斯琴森效应。恰好在这个频率下，这两种材料的折射率相等，且吸收系数非常小。此外，它对于制作新型带通滤波器或正确测定某些材料的折射率等非常有用。
