Mass‐independent isotope effects and their use in understanding natural processes

• Published in: Israel Journal of Chemistry
• Main Author: Thiemens, Mark H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2002
• Subjects: General Chemistry; Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1560/vm6g-lwec-h5ex-39nr; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1560%2FVM6G-LWEC-H5EX-39NR; https://onlinelibrary.wiley.com/doi/pdf/10.1560/VM6G-LWEC-H5EX-39NR

Abstract In 1983, Thiemens and Heidenreich ( Science 219 , 1073) reported the discovery of a mass‐independent isotope process in oxygen. Subsequently, mass‐independent isotopic compositions were observed in meteorites, atmospheric O 2 , CO 2 , O 3 , H 2 O 2 , CO, N 2 O, and aerosol sulfate and nitrate. In addition, solid samples from the Namibian Desert, Antarctic dry valleys, Miocene volcanic ash, and Death Valley varnishes all possess mass‐independent isotopic compositions that have permitted new scientific insights to be obtained. Sulfur mass‐independent isotopic anomalies in Precambrian samples have provided a completely new mechanism to track atmospheric O 2 levels and the evolution of life from ∼3.9 to 2.2 × 10 9 years ago. Measurements of mass‐independent isotopic compositions in Martian meteoritic sulfates and carbonates have also provided new information on Martian atmosphere‐regolith interactions and history. In sum, the use of mass‐independent isotopic compositions has advanced a wide range of geo‐ and cosmo‐chemical frontiers. In addition, these newly discovered effects have provided a new means to probe the chemical physics of molecular transition state theory.