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

尽管C14放射性碳法的引入带来了突破性的进展，但在考古组合的年代测定中仍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，即使在放射性测量精度很高的情况下，也会在定年范围内产生长达300年的不确定性。这是一种全新的人工制品年代测定方法，基于对古代陶瓷的再羟基化反应的记录，完全独立于C14年代测定，因此受到了全世界考古学家的高度欢迎。这种新方法是基于这样一种观察，即陶瓷的质量在烧制后，只与时间的四分之一（而不是平方根）成比例地增加。这种时间依赖性（随着时间的增加而变得越来越弱）将潜在地允许确定给定陶瓷制品生产的时间，即，通过烧制，它已经转移到去羟基化状态并开始了再羟基化过程。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性。在目前的项目中，我们的目标是应用两种经过验证的材料表征技术，为探索产生这种显著的、高度延迟的再羟基化时间依赖性的基本机制做出贡献。利用这两种技术，特别是利用不同的核磁共振波谱和红外显微成像技术，我们对许多主客体系统进行了广泛的研究，包括观察物质释放和摄取，就像在脱羟基和再羟基化过程中观察到的一样，这是研究问题的关键现象。在一系列的测试实验中，我们已经能够证明这两种技术都适用于给定上下文中感兴趣的材料，而且，我们因此确实能够访问预定模型考虑所必需的信息。在测试实验和我们未来工作的构想中，我们都依赖于该领域领先专家的建议和建议，包括时间异常的发现者，以及弥合材料科学和考古学之间差距的“大使”。

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.