First Experimental Determination of the Ionization Potentials of Berkelium and Californium
First Experimental Determination of the Ionization Potentials of Berkelium and Californium
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锫和锎电离势的首次实验测定
DOI：
10.1002/anie.199628561
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发表时间：
1996
影响因子：
--
通讯作者：
N. Trautmann
中科院分区：
文献类型：
--
作者：
S. Köhler;N. Erdmann;M. Nunnemann;G. Herrmann;G. Huber;J. Kratz;G. Passler;N. Trautmann
第一电离势是元素的基本性质，对于许多物理和化学过程非常重要。它的精确测定使人们能够识别元素与元素之间结合能的系统趋势，并得出原子电子结构的结论，因为第一电离势直接与原子光谱相关：能级可以以（负）结合能给出，其中电离势代表能量零点，也可以以（正）激发能给出。在这种情况下，n+ r 的能级能量En；。收敛于电离势。需要有关最重元素的电子结构的可靠信息，以便能够说明元素周期表的规律性是否通过这些元素得以维持，或者它们是否受到干扰。“‘第一电离势是一种敏感地依赖于相对论效应的属性，相对论效应是由于内部电子的相对论质量增加而在最重元素中预期的。[’I这些元素的第一电离势的精确确定可以服务作为对相对论多构型狄拉克-福克计算的预测的检验。~~~ 此外，第一电离势是玻恩-哈伯循环中的一个重要量。通过激光光谱方法已经获得了最精确的电离势。通过长系列高度收敛，可以非常精确地确定镧系元素以及铀和较轻的超铀元素镎和钚的第一电离势。由于构型相互作用，需要大量数据才能正确解释光谱。Worden 等人 [81] 测定了钚的第一电离势，显示了该方法的局限性：必须使用最多 2 g 的放射性 239Pu。
The first ionization potential is a fundamental property of an element and is of great importance for many physical and chemical processes. Its accurate determination enables one to identify systematic trends in binding energies from element to element, and to draw conclusions on the electronic structure of atoms, since the first ionization potential is directiy connected to the atomic spectrum: The energy levels can either be given as (negative) binding energies, where the ionization potential represents the energetic zero point, or as (positive) excitation energies. In this case the level energy En for n+ r;. converges to the ionization potential.Reliable information about the electronic structure of the heaviest elements is needed to be able to state whether the regularities of the Periodic Table of Elements are maintained up through these elements or whether they are disturbed.“’The first ionization potential is a property that sensitively depends on relativistic effects, which are expected in the heaviest elements as a result of the relativistic mass increase of the inner electrons.[’I The precise determination of the first ionization potential of these elements can serve as a test of the predictions of relativistic multiconfiguration Dirac-Fock calc~ lations.~~~ Furthermore, the first ionization potential is an important quantity in the Born-Haber cycle. r41 The most accurate ionization potentials have been obtained by laser spectroscopic methods. The first ionization potentials of the lanthanide elements as well as those of uranium and the lighter transuranium elements neptunium and plutonium have been determined very accurately from the convergence of long series of highly excited Rydberg A large amount of data is required for a correct interpretation of the spectra, due to configuration-interactions. The determination of the first ionization potential of plutonium by Worden et a1.[81 shows the limitations of the method: up to 2 g of radioactive 239Pu had to be used.