球形α-Fe2O3超微粒的红外光学特性和表面模吸收

用改进的水解法制备了大小均匀、形状规则的球状α-Fe₂O₃超微粒;分别测量了两种不同粒度超微粒的红外透射谱;观测到了球状α-Fe₂O₃超微粒的全部表面模;讨论了微粒的聚集对吸收的影响;并用柱状微晶来近似链状聚集解释了光谱中的两个展宽吸收带;介绍了将多原子立方结构超微粒的表面模理论推广应用到单轴晶体结构的α-Fe₂O₃超微粒的情况。对表面模吸收频率进行了计算,理论数据同实验结果 关键词：

SURFACE MODE ABSORPTION AND INFRARED OPTICAL PROPERTIES OF SMALL SPHERICAL α-Fe2O3 PARTICLES

The small spherical α-Fe₂O₃ particles with uniform size and regular shape were prepared by improved hydrolysis method. The infrared transmisson spectra of this two kinds of particles different in dimension were measured, and all surface modes of small spherical α-Fe₂O₃ particles were obtained. The effect of aggregation on absorption were discussed, and the two absorption bands in spectra were explained with the approximation of chain aggregation by cylindrical microcrystals. Surface mode theory of multi-atomic cubic particles was generalized and applied to α-Fe₂O₃ particles in monoaxial crystal structure. The theoretical results of surface mode frequency of α-Fe₂O₃ particles were presented, which agreed well with those of experiments. The existence of generalized modified LST relation was verified.