Coherence refers to correlations in waves. Because matter has a wave-particle nature, it is unsurprising that coherence has deep connections with the most contemporary issues in chemistry research (e.g., energy harvesting, femtosecond spectroscopy, molecular qubits and more). But what does the word “coherence” really mean in the context of molecules and other quantum systems? We provide a review of key concepts, definitions, and methodologies, surrounding coherence phenomena in chemistry, and we describe how the terms “coherence” and “quantum coherence” refer to many different phenomena in chemistry. Moreover, we show how these notions are related to the concept of an interference pattern. Coherence phenomena are indeed complex, and ambiguous definitions may spawn confusion. By describing the many definitions and contexts for coherence in the molecular sciences, we aim to enhance understanding and communication in this broad and active area of chemistry.

中文翻译：

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化学中的相干性：基础和前沿


相干性是指波中的相关性。由于物质具有波粒性质，因此相干性与化学研究中最现代的问题（例如，能量收集、飞秒光谱、分子量子比特等）有着深厚的联系也就不足为奇了。但是，在分子和其他量子系统的背景下，“相干性”这个词的真正含义是什么？我们回顾了化学中相干现象的关键概念、定义和方法，并描述了术语“相干”和“量子相干”如何指代化学中的许多不同现象。此外，我们还展示了这些概念与干涉图案的概念有何关系。相干现象确实很复杂，模棱两可的定义可能会产生混淆。通过描述分子科学中相干性的许多定义和背景，我们旨在加强对这一广泛而活跃的化学领域的理解和交流。