weight: bold" lang=EN-US>A Common Mistake Involved in Stable Isotope Fractionation Calculation

• 责任者：Liu Qi (State Key Laboratory of Ore Deposit Geochemistry ; Institute of Geochemistry ; Chinese Academy of Sciences ; Guiyang 550002 ; China) ; Tang Mao
• 刊名：Acta Mineralogica Sinica
• 出版年：2009
• 卷期：29(2)
• 关键词：稳定同位素 ; stable isotopes ; 同位素分馏作用 ; isotope fractionation
• 页码：p.175-182
• 图表：2 tables, 29 refs.
• 分类号：0600
• issnNo：ISSN1000-4734
• isbnNo：CN52-1045/P

The Urey model or the so-called Bigeleisen-Mayer equation has been the theoretical corner-stone of stable isotope geochemistry for decades. As for the use of this model, it needs vibrational frequency positions for different isotope-substituted molecules to calculate the equilibrium constant of the isotope exchange reaction. There are several approximations used in the Urey model, such as the harmonic oscillator and rigid rotator treatments. It also uses the Redlich-Teller product law to further simplify the formulation. These approximations require that only harmonic frequencies be used in the Urey model. By reiterating the key steps of the deduction process of the Urey model, the authors showed how important it is to use the pure harmonic frequencies in the Urey model.