ABSTRACT
The micro Raman spectra of solid-liquid boundary layer, the melts and crystal side, were measured at real time, concerning BSO crystal grown with zone-melting method. The structure characters in boundary layer, melts and crystal were analyzed. The process, of which the growth unit structure changed while they transited from melts through boundary layer to crystal lattice, was analyzed. The results show that, there exists Bi3O4 and [SiO4] bonding structure in the melts of BSO crystal. While in the solid-liquid boundary layer, the Bi3O4 molecular units converge into [BiO7] octahedron monomer of polymer in form, the monomer or the polymer converge with the [SiO4] structure units, then all these converged structure enter into crystal lattice sites.
Subject(s)
Bismuth/chemistry , Oxides/chemistry , Silicon Compounds/chemistry , Spectrum Analysis, Raman/methods , Crystallization , Models, Chemical , Polymers/chemistry , Surface Properties , Temperature , Time FactorsABSTRACT
The structure character of BSO crystal at room temperature was generalized. The main Raman shifts of lattice vibration at room temperature were interpreted. The Raman spectra of BSO crystal were measured in a temperature range from 293 K to 1123 K with high temperature Raman spectroscopy and time-resolved detection techniques. Temperature-dependence character of the Raman spectra of the crystal was investigated. The vibration mode of the longest bond Bi-O(1) in crystal shifts from 542 cm(-1) to 512 cm(-1) with the temperature increasing from room temperature to 1123 K. It can be attributed to the fact that oxygen atoms are electrostatic bond to Bi atoms. The intensity of 88 cm(-1) modes, which belongs to combination mode of bending and stretching in Bi3O4 unit, changes not so noticeably as other modes, and even the 58 cm(-1) mode of Bi atoms motions in crystal lattice decreases rapidly when the temperature is higher than 873 K, which indicates that the framework structure of the crystal is broken down at high temperature, while the Bi3O4 unit still exists.
Subject(s)
Bismuth/chemistry , Hot Temperature , Oxides/chemistry , Silicon Compounds/chemistry , Spectrum Analysis, Raman/methods , Crystallization , Models, Molecular , Oxygen/chemistry , Silicon Dioxide/chemistryABSTRACT
The room temperature and high temperature Raman spectra of solid/melt growth boundary layers of TeO2 grown from melt were measured by high-temperature laser-micro-Raman spectrum. By analyzing, vibrational modes of the room temperature Raman spectra peaks of TeO2 crystal from band 200-800 cm-1 were confirmed, the expansion and frequency shift of each peak of the high temperature Raman spectra were interpreted and the possible structure group of the melt was proposed. So, certain foundation for studying the growth theory of functional crystal materials was provided.
