摘要
氧同位素的非质量依赖分馏研究是稳定同位素地球化学领域的重要组成部分,是太阳系星云演化、早期大气圈演化及全球变化研究的一个无以替代的方式。近年来,随着微小非质量依赖分馏研究(微小氧-17异常)的兴起,对不同同位素交换过程的质量依赖分馏线(MDFL)的位置,提出了前所未有的要求,这个新兴领域的发展依赖于高精度质量依赖分馏线的存在。从质量依赖分馏线斜率λ的定义式出发,指出精确计算λ值的方式,并利用高级量子化学计算方法,系统研究了λ的过程及温度依赖性,分析了拐点产生的条件。本研究将为今后大量开展的微小非质量依赖分馏研究打下基础,同时一些计算结果可为实验室精确检测17O及微小17O异常的解释所使用。
Oxygen isotope mass-independent fractionation （MIF） study is an important part of stable isotope
geochemistry. It plays a crucial role in studies of early solar nebular condensation process, the evolution of
atmosphere of early Earth and the global climate changes. Recently, along with the emerging field of so-called
small MIF study （O-17 anomaly study）, the accurate positions of mass-dependent fractionation line （MDFL） of
various isotope exchange reactions have become a prerequisite condition for such kind of research. The small MIF
study is largely depended on the existing of precise MDFL. This study, beginning with the definition of the slope
of MDFL （i.e. λ value）, deduces out the theoretical method for precisely calculating λ values. The process
dependence and the temperature dependence characteristics of λ values are systematically studied via high level
quantum chemistry calculations. The cross-over temperature of λ value is also discussed. This study will help the
development of the emerging field of small oxygen-17 anomaly studies.
出处
《地球化学》
CAS
CSCD
北大核心
2011年第2期147-155,共9页
Geochimica
基金
国家自然科学基金(40773005
41073015)
国家高技术研究发展计划(No.2010AA1222)
矿床地球化学国家重点实验室专项经费
