NMR and IR-imaging of mass transfer during rehydroxylation of fired clays for rationalizing a novel dating concept of antique artefacts

尽管采用C14放射性碳法取得了开创性的进展，但在考古组合的年代测定方面仍然存在很大的不确定性。它们是由校准曲线中的“放射性碳高原”引起的，在某些时期，即使放射性测量的精度很高，也会在测年范围内产生长达300年的不确定度。因此，以记录古陶瓷的再羟化为基础，完全独立于C14测年的新方法获得文物年代的选择，受到了全球考古界的高度欢迎。这种新的方法是基于这样的观察，即陶瓷在烧成后，质量只与时间的四次根(而不是平方根)成比例增加。这种时间依赖性(随着时间的增加而变得越来越弱)可能允许确定特定陶瓷制品的生产时间，即通过烧成，它何时转变为脱羟基状态并开始重新羟化过程。然而，到目前为止，还没有任何令人满意的模型来解释这种特殊的时间依赖关系。在本项目中，我们的目标是应用两种经过验证的材料表征技术来帮助探索导致这种显著的、高度延迟的重新羟基化的基本机制。使用这两种技术，特别是不同的核磁共振光谱修改和红外显微镜显微成像，我们对许多主客体系统进行了广泛的研究，包括观察物质的释放和摄取，以及在脱羟基和再羟化过程中观察到的关键现象。在一系列测试实验中，我们已经能够证明这两种技术都适用于特定背景下感兴趣的材料，而且，因此，我们确实可以获得预定模型考虑所需的信息。在测试实验和我们未来工作的构想中，我们依靠该领域领先专家的建议和建议，包括时间反常的发现者，并通过“大使”弥合材料科学和考古学之间的差距。

Irrespective of the groundbreaking progress initiated by the introduction of the C14 radio-carbon method, there are still substantial uncertainties in the dating of archaeological assemblages. They are caused by the "radiocarbon Plateaus" in the calibration curves, which, in some periods, give rise to uncertainties up to 300 years in the dating ranges, even with the high precision in radioactivity measurement. The option of a novel access to the dating of artefacts, based on recording the rehydroxylation of antique ceramics and totally independent from C14 dating, was therefore highly welcomed by the worldwide archaeologists’ community. This novel method is based on the observation that the mass of ceramics, after having been fired, increases in proportion to only the quartic (rather than the square) root of time. Such a time dependence (becoming increasingly weak with increasing time) would potentially allow determining the time when a given ceramic artefact has been produced, i.e. when, by firing, it has been transferred into the dehydroxylated state and has started the process of rehydroxylation. However, so far there does not exist any satisfactory model explaining this peculiar time dependence.Within the present project, we aim at the application of two well-proven techniques of material characterization for contributing to the exploration of the elementary mechanisms giving rise to this remarkable, highly retarded time dependence of rehydroxylation. With both techniques, notably with different modifications of NMR spectroscopy and with micro-imaging by IR microscopy, we have performed extensive investigations of numerous host-guest systems, including the observation of matter release and uptake just as to be as well observed during de- and rehydroxylation as the key phenomena of the problem under study. In a series of test experiments, we have been able to demonstrate that both techniques are applicable to the materials of interest within the given context and that, moreover, we thus indeed have access to the information necessary for the scheduled model considerations.In both the test experiments and the conception of our future work, we have relied on the suggestions and the advice by leading experts in the field, including the discoverers of the time anomaly, and by "ambassadors" bridging the gap between material sciences and archaeology.