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Studies on Spectroscopy of Rare Earth Oxides and Minerals

Author: XueLiHui
Tutor: YuanRunZhang
School: Wuhan University of Technology
Course: Materials Science
Keywords: Rare earths Raman spectra Vibration infrared spectroscopy Electronic infrared spectroscopy Photoluminescence spectra Vis absorption spectra Stark splitting Annealing
CLC: TB39
Type: PhD thesis
Year: 2003
Downloads: 778
Quote: 6
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Abstract


Spectra complex and changeable, the study of rare earth spectra not only rich in rare earth knowledge, but also to lay the theoretical foundation for the study of rare earth materials. This work of rare earth oxides and a number of typical rare earth mineral spectra, the purpose is to determine the characteristics and mechanism, and clarify the relationship between the various Spectra. The thesis is divided into two parts: (1) study of Raman spectroscopy and vibration infrared spectroscopy; (2) of the electronic spectra, photoluminescence spectroscopy, visible absorption spectrum, infrared spectroscopy of the electronic Raman spectroscopy and electronic research. 1. Three micro-Raman spectroscopy and different excitation light, including laser wavelength 325.0nm, 457.9nm, 488.0nm, 514.5nm, 632.8nm and 785.0nm six, to obtain samples of the Raman spectrum. System using Raman spectroscopy and infrared spectroscopy analysis of the vibration characteristics of the sample, the main results are as follows: (1) first reported nine C-type (cubic) complete rare earth oxides at 400 to 800cm of -1 -infrared spectral region and 80 to 800cm of -1 Raman spectra vibrational spectroscopy. These data indicate that the vibration frequency depends on the crystal structure reveals the lanthanide contraction effect on the frequency of vibration regularity. The authors found that the C-type Yb 2 O 3 Raman spectroscopy with unusual phenomena, not only the shape of its spectrum is different from the other C-type oxide, and the peak position is not lanthanide contraction law. Authors believe the Yb 2 O 3 special Raman spectroscopy may reflect Yb 3 Electronic Raman spectra of Yb 2 O 3 Raman spectra of the mixed spectrum or coupling spectrum of Yb 2 O 3 special Raman spectroscopy effect may be involved in the key issues of the electronic Raman spectral theory. (2) light RE 2 O 3 (RE = La, Pr, Sm) in the air easily hydration and carbonation. By Raman spectroscopy, infrared spectroscopy and X-ray diffraction to determine the hydration and carbonation product of RE (OH) 3 , RE six-party 2 O 2 CO 3 , Quartet RE 2 O 2 the CO 3 and RE 2 O (CO 3 ) 2 . Precise determination of Pr 6 O 11 the hydration phase Pr Standard (OH) 3 crystallographic parameters, the result is: hexagonal, space group P6 3 / m and a = .6465, c = .3759, Z = 2, D x = 4.684g/cm 3 . Supplement Pr (OH) 3 the JCPDS diffraction Card (45-86) missing data, correct indicator of error of the two diffraction peaks. (3) variable ecological minerals Raman spectrum is weak, the linewidth dispersion, while the annealing crystalline minerals Raman spectrum sharp. Determine the the fergusonite group minerals, the group minerals aeschynite, monazite and fluoro-carbonate minerals characteristic Raman and infrared vibrational frequency, and vibration peaks were assigned. The mineral composition and structure of the vibrational spectra. 2. The main results are as follows: (1) the design of a high-resolution visible light absorption spectrum of a Raman spectrometer for visible light absorption spectrum of the new method, this method can establish a rare earth compounds Raman study of the electronic spectra spectroscopy, photoluminescence and IR spectra, an important role in its recognition complex Spectra explore the mechanism of the emission and absorption. Xue Hui Wuhan University Doctoral Dissertation Abstract (2) found that at room temperature, in Boltzm Brunet role in the electronic ground states and excited-state interband transition of RE3 luminous bands and absorption the location of the peak of the band in fine-to explain the reasons for this relationship, and figure out what the ground state Er203 in the Er3 the electronic state 4lts.12 and excited electronic state where / 2,4 where / 2 stark level splitting situation to determine room temperature ErZO3 Er3 4 15/2 2 where / 2 'I 5/2' where / 2 fine level transition form. (3) introducing the concept of the electronic infrared spectra, and with common infrared spectra i.e. vibration infrared spectrum is different, the electronic infrared spectrum from the absorption transition between the electron energy levels. Found EuZq 400 a 4o00cm 'the vast majority of the infrared spectral region peaks and NdZ's, the fluorocarbon bell barium mine, fluorocarbon calcium Bell Mine, Yellow River mine, fluorocarbon Bell Mine in, 1650 a 32O0cm' spectral region infrared peaks from E ore and the the Nd3 absorption transition of the electron energy levels to determine the room temperature in EuZ pseudo Eu3 'F0; stark level splitting of electronic states and' D. 7F0 an eleven; forms of transitions between the fine level. (4) that does not emit light in the visible region LaZO3, YZ Qiu and LuZO3, the spectra of pure samples in strong luminescence phenomena visible laser excitation, the spectra of the three samples were derived from samples of trace sm3, Er, Eu,. (5) Variable emission band and absorption spectrum bandwidth of the eco-rare earth mineral dispersion after heating bands obviously becomes sharp. Crystalline rare earth minerals has a class of linear luminescence and absorption bands are closely related, and the shape and position of the bands with mineral chemical composition, crystal structure and excited. Presented and brown Yi Ni group minerals, the aeschynite group minerals monazite and rare earth fluoro-carbonate minerals under 488.OIun and 514.5tun laser excitation photoluminescence spectra to determine the nature of the photoluminescence center. In addition, it was found that the absorption of these minerals visible mainly Nd3 absorption, Nd3 may be the mineral photoluminescence important sensitizer.

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