Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, 92093, USA.
Angew Chem Int Ed Engl. 2019 May 20;58(21):6826-6844. doi: 10.1002/anie.201812322. Epub 2019 Feb 14.
Stable isotope ratio measurements have been used as a measure of a wide variety of processes, including solar system evolution, geological formational temperatures, tracking of atmospheric gas and aerosol chemical transformation, and is the only means by which past global temperatures may be determined over long time scales. Conventionally, isotope effects derive from differences of isotopically substituted molecules in isotope vibrational energy, bond strength, velocity, gravity, and evaporation/condensation. The variations in isotope ratio, such as O/ O (δ O) and O/ O (δ O) are dependent upon mass differences with δ O/δ O=0.5, due to the relative mass differences (1 amu vs. 2 amu). Relations that do not follow this are termed mass independent and are the focus of this Minireview. In chemical reactions such as ozone formation, a δ O/δ O=1 is observed. Physical chemical models capture most parameters but differ in basic approach and are reviewed. The mass independent effect is observed in atmospheric species and used to track their chemistry at the modern and ancient Earth, Mars, and the early solar system (meteorites).
稳定同位素比测量已被广泛应用于各种过程的测量，包括太阳系演化、地质形成温度、大气气体和气溶胶化学转化的追踪，以及过去全球温度在长时间尺度上的唯一测定手段。传统上，同位素效应源于同位素振动能量、键强度、速度、重力和蒸发/冷凝中同位素取代分子的差异。同位素比值的变化，如 O/ O（δ O）和 O/ O（δ O），取决于质量差异，δ O/δ O=0.5，这是由于相对质量差异（1 amu 与 2 amu）。不遵循这种关系的被称为质量无关，是本综述的重点。在臭氧形成等化学反应中，观察到 δ O/δ O=1。物理化学模型捕捉到了大多数参数，但在基本方法上有所不同，并进行了综述。这种质量无关的效应在大气物种中被观察到，并用于追踪它们在现代和古代地球、火星和早期太阳系（陨石）中的化学性质。
