Pb+ irradiation of synthetic zircon (ZrSiO4): Infrared spectroscopic investigation
- University of Cambridge
- ORNL
- University of Michigan
The structural variations of synthetic zircon (ZrSiO{sub 4}) single crystals irradiated at room temperature by 280 keV Pb{sup +} ions (with fluences up to 1 x 10{sup 15} ions/cm{sup 2}) were investigated using infrared (IR) spectroscopy. Like metamict zircon whose crystal structure is damaged and amorphized by naturally occurring {alpha}-decay events, the Pb{sup +}-irradiated zircon crystals show a dramatic decrease in reflectivity. However, no significant decrease in wavenumbers of the stretching vibrations of SiO{sub 4} tetrahedra in zircon was detected. The Pb{sup +}-implanted zircon exhibits new IR bands, indicating irradiation-induced new vibrations or domains, clusters or phases in addition to SiO{sub 2} and ZrO{sub 2}. IR features consistent with those of Pb silicates (with a divalent state, i.e., Pb{sup 2+}) are also found in the irradiated sample. This finding implies that some of the radiogenic Pb in natural zircon might not actually reside in the zircon lattice or in ZrSiO{sub 4} phases, but form new local domains or clusters. Infrared bands of OH-stretching vibrations were also detected in the irradiated synthetic zircon, which was originally free from OH features prior to the irradiation. These results indicate that H can easily diffuse into the irradiated layer or into irradiated-induced phases to form OH or and hydrous species after the irradiated material is damaged. The type and content of hydrous species vary with irradiation fluences.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 979585
- Journal Information:
- American Mineralogist, Vol. 93, Issue 8-9; ISSN 0003-004X
- Country of Publication:
- United States
- Language:
- English
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