title: [Effect of surface decoration on the spectral characteristics of alpha-Fe2O3 ultrafine particles].
abstract: The alpha-Fe2O3 ultrafine particles were equally dispersed in the solutions of stearic acid/n-hexane/chloroform by the ultrasonic method, the surfaces of the alpha-Fe2O3 ultrafine particles were decorated by stearic acid, and the alpha-Fe2O3 ultrafine particles decorated had very good flowage characteristic. Before alpha-Fe2O3 ultrafine particles were decorated, the UV absorption was very strong at wavelengths shorter than 290 nm, and there was a shoulder peak at 330 nm. The absorption band edges of alpha-Fe2O3 ultrafine particles was at 392 nm, and shifted toward blue, which was in contrast with that of bulk Fe2O3. This was caused by the quanta size effect and surface effect. IR characteristic peaks of the alpha-Fe2O3 ultrafine particles appeared at 524.36 and 446.37 cm-1. After alpha-Fe2O3 ultrafine particles were decorated, the absorption side moved from 392 to 896 nm, which significantly shifted to the red in contrast with that of bulk F2O3. The vibration of Fe-O bond moved from 524.36 to 521.33 cm-1 and from 446.37 to 443.34 cm-1, respectively. These were caused by the dielectric confinement effect. The relative intensity of X-ray diffraction obviously increased, and the diffraction peak size moved toward the direction of smaller diffraction angle after the alpha-Fe2O3 ultrafine particles were decorated.
authors.affiliation: Physics Department, Yancheng Teachers' College, Yancheng 224002, China.
authors.forename: Cheng-lin
authors.initials: CL
authors.lastname: Liu
authors.forename: Ju-hua
authors.initials: JH
authors.lastname: Zhong
authors.forename: Zhao-kui
authors.initials: ZK
authors.lastname: Zhang
mesh_terms: D002725:Chloroform; D003102:Colloids / Q000737:chemistry*; D004563:Electrochemistry; D005296:Ferrous Compounds / Q000737:chemistry*; D006586:Hexanes; D010316:Particle Size; D052638:Particulate Matter; D012666:Semiconductors; D012828:Silicones / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013229:Stearic Acids; D013499:Surface Properties; D014732:Vibration; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D003102:Colloids; D005296:Ferrous Compounds; D006586:Hexanes; D052638:Particulate Matter; D012828:Silicones; D013229:Stearic Acids; C026385:n-hexane; C031183:stearic acid; D002725:Chloroform; C034236:ferrous oxide