Nuclear resonance vibrational spectroscopy (NRVS; also known as nuclear inelastic scattering, NIS) is a synchrotron-based method that reveals the full spectrum of vibrational dynamics for Mössbauer nuclei. Another major advantage, in addition to its completeness (no arbitrary optical selection rules), is the unique selectivity of NRVS. The basics of this recently developed technique are first introduced with descriptions of the experimental requirements and data analysis including the details of mode assignments. We discuss the use of NRVS to probe ⁵⁷Fe at the center of heme and heme protein derivatives yielding the vibrational density of states for the iron. The application to derivatives with diatomic ligands (O₂, NO, CO, CN^–) shows the strong capabilities of identifying mode character. The availability of the complete vibrational spectrum of iron allows the identification of modes not available by other techniques. This permits the correlation of frequency with other physical properties. A significant example is the correlation we find between the Fe–Im stretch in six-coordinate Fe(XO) hemes and the trans Fe–N(Im) bond distance, not possible previously. NRVS also provides uniquely quantitative insight into the dynamics of the iron. For example, it provides a model-independent means of characterizing the strength of iron coordination. Prediction of the temperature-dependent mean-squared displacement from NRVS measurements yields a vibrational “baseline” for Fe dynamics that can be compared with results from techniques that probe longer time scales to yield quantitative insights into additional dynamical processes.

中文翻译：

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从核共振振动光谱学到的东西：振动动力学和血红素

核共振振动光谱法（NRVS；也称为核非弹性散射，NIS）是一种基于同步加速器的方法，它揭示了Mössbauer核的整个振动动力学光谱。除了其完整性（没有任意的光学选择规则）外，另一个主要优点是NRVS具有独特的选择性。首先介绍这种最新开发的技术的基本知识，并描述实验要求和数据分析，包括模式分配的详细信息。我们讨论了使用NRVS探测血红素和血红素蛋白衍生物中心的⁵⁷ Fe，产生铁的态振动密度。具有双原子配体（O ₂，NO，CO，CN ^–）显示了识别模式字符的强大功能。铁的完整振动谱的可用性允许识别其他技术无法获得的模式。这允许频率与其他物理特性相关。一个重要的例子是我们发现六坐标的Fe（XO）血红素中的Fe–Im延伸与反式Fe–N（Im）的键距之间的相关性，以前是不可能的。NRVS还提供了对铁动力学的独特定量定量见解。例如，它提供了与模型无关的表征铁配位强度的方法。