IR stimulation spectroscopy of plagioclase and potassium feldspars, and quartz
IR stimulation spectroscopy of plagioclase and potassium feldspars, and quartz
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DOI：
10.1093/oxfordjournals.rpd.a031759
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发表时间：
1996-01-01
影响因子：
1
通讯作者：
Cada, M
中科院分区：
文献类型：
--
作者：
GodfreySmith, DI;Cada, M
从动力学和其他研究中得知，不同长石种类的TL发光曲线之间的差异是由于电荷陷阱分布的差异。推测不同长石种类的激发光谱也应该不同是合理的。在努力确定的范围内的差异刺激光谱的矿物有用的地质年代学研究，近红外刺激光谱的微斜长石，斜长石，石英提取物，和长石为主的提取物从沉积物进行了测量。所有样品进行预处理，以确保只有从热稳定陷阱驱逐的载流子参与发光过程。在所有样品中发现单一刺激峰。它位于845 nm处的所有微斜长石，最斜长石，和所有的长石为主的沉积物提取物，并在840 nm处的两个几乎纯钠斜长石以及所有的石英提取物。微斜长石的光谱最窄，半高宽为0.127 eV（近似于80 nm）。峰宽为0.138 eV（88 nm）。增加的Ca含量使峰向较长波长加宽了约5 nm，而增加的Na含量使峰向较短波长加宽了高达10 nm。斜长石OMGB在845+/-0.1 nm处的峰位置得到确认。在石英提取物中发现了类似于斜长石的宽光谱，尽管其强度比长石低1至2.5个数量级。这表明，刺激光谱是由于Al 3+（碱）（+）络合物，这是一个主要的（按重量计约25%）的结构成分，在所有的长石，和一个共同的杂质取代Si 4+在天然石英。对于所有未来的IRSL实验，建议用调谐到845 nm的半导体二极管激光器代替LED二极管激励。
It is known from kinetic and other studies that the differences between TL glow curves of different feldspar species are due to differences in charge trap distributions. It is reasonable to presume that stimulation spectra of different feldspar species should also differ. In an effort to determine the range of differences in the stimulation spectra of minerals useful in geochronolog ical studies, the near-IR stimulation spectra of microclines, plagioclases, quartz extracts, and feldspar-dominated extracts from sediments were measured. All samples were pretreated to ensure that only carriers evicted from thermally stable traps were involved in the luminescence process. A single stimulation peak was found in all samples. It lies at 845 nm in all microclines, most plagioclases, and all feldspar-dominated sediment extracts, and at 840 nm in two nearly pure Na plagioclases as well as all quartz extracts. Microclines showed the narrowest spectrum, with a 0.127 eV (similar to 80 nm) FWHM. Peak width of oligoclases was 0.138 eV (88 nm) FWHM. Increased Ca content broadened the peak by similar to 5 nm towards longer wavelengths, while increased Na content broadened it by up to 10 nm towards shorter wavelengths. The position of the peak at 845+/-0.1 nm was confirmed for plagioclase OMGB. A broad spectrum similar to that of plagioclases is found in quartz extracts, although its intensity is lower by 1 to 2.5 orders of magnitude from that of feldspars. It is suggested that the stimulation spectrum is due to an Al3+ (alkali)(+) complex, which is a major (similar to 25% by weight) structural component in all feldspars, and a common impurity substituting for Si4+ in natural quartz. For all future IRSL experiments it is suggested that LED diode stimulation is replaced by a semiconductor diode laser tuned to 845 nm.