新聞動(dòng)態(tài)2025.06.23?New Measurements and Theory of Mass Independent Isotope Effects and Relation to Archean, Atmosphere and Solar System Origin Using?Quantum Dynamics
? ? ? ? 應(yīng)林莽研究員邀請(qǐng)，加州大學(xué)圣地亞哥分校(UCSD)化學(xué)與生物化學(xué)系講席講授Mark Thiemens院士?將于6月23日（下周一）訪問(wèn)我所并在標(biāo)本樓308會(huì)議室做學(xué)術(shù)報(bào)告，歡迎大家參加并積極討論！
? ? ? ? 報(bào)告題目：New Measurements and Theory of Mass Independent Isotope Effects and Relation to Archean, Atmosphere and Solar System Origin Using? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Quantum Dynamics
? ? ? ??報(bào) 告 人：Mark Thiemens 院士（加州大學(xué)圣地亞哥分校）
??? ? ? ? 報(bào)告時(shí)間：6月23日（周一）上午10:30
??? ? ? ? 報(bào)告地點(diǎn)：標(biāo)本樓308會(huì)議室? ??
? ? ?報(bào)告人簡(jiǎn)介：
? ? ? Mark Thiemens院士是加州大學(xué)圣地亞哥分校(UCSD)化學(xué)與生物化學(xué)系講席講授，曾任UCSD自然科學(xué)學(xué)部創(chuàng)辦主任(2000-2016)。Thiemens院士主要從事同位素地球化學(xué)、大氣化學(xué)、宇宙化學(xué)等方面的研究，他發(fā)現(xiàn)了化學(xué)過(guò)程產(chǎn)生的同位素非質(zhì)量依賴分餾效應(yīng)(MIF) ，開(kāi)拓了MIF在地球和行星科學(xué)的廣泛應(yīng)用，在多個(gè)研究領(lǐng)域發(fā)表了多篇具有影響力的論文，其中Science 22篇、Nature 8篇、PNAS 23篇。Thiemens院士是美國(guó)科學(xué)院院士和英國(guó)皇家學(xué)會(huì)外籍院士，Goldschmidt獎(jiǎng)?wù)?地球化學(xué)學(xué)會(huì))、Leonard獎(jiǎng)?wù)?隕石學(xué)會(huì))等國(guó)際學(xué)會(huì)最高榮譽(yù)獲得者，AGU、GS、EAG等學(xué)會(huì)會(huì)士，目前是PNAS的地學(xué)編委。
? ? ? ? Abstract：? ? ?
The measurement of stable isotopes in natural phenomena dates back to 1947 when an equilibrium isotope exchange model of isotopes was developed by Urey and the stable isotope ratio mass spectrometer was developed by Nier. Since then, the applications have been extensive. The temperature of Earth’s surface is obtained by carbonate oxygen isotopes and polar ice. The rise and fall of polar ice may be determined for the Earth. The temperature of rock formations between minerals was also an early application. Gravity effects on the escape of nitrogen and argon isotopes from the Martian atmosphere have allowed models to be created. Kinetic effects in biological systems have covered many topics, ranging from global primary productivity to metabolic process definitions.
? ?A new class of isotope effects not reliant upon mass were discovered and explored by Thiemens and include photochemistry effects in the atmosphere, origin of the solar system, and, using sulfur isotopes many groups have developed understanding of the origin and evolution of life. A limit in our ability to model these systems at high resolution is that we do not know the isotope fractionation of photodissociation as a function of energy.?The effects are in the UV range, and it is impossible to measure across the spectrum because one needs a synchrotron, and it requires a day for a single measurement. What is needed is a theory that allows one to calculate these effects. In this talk, new applications of quantum effects that have never been included before are discussed and the theory and measurements are shown.
