Gendron Frédéric, Fleischauer Valerie E, Duignan Thomas J, Scott Brian L, Löble Matthias W, Cary Samantha K, Kozimor Stosh A, Bolvin Hélène, Neidig Michael L, Autschbach Jochen
Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA.
Phys Chem Chem Phys. 2017 Jul 5;19(26):17300-17313. doi: 10.1039/c7cp02572f.
We present a combined ab initio theoretical and experimental study of the magnetic circular dichroism (MCD) spectrum of the octahedral UCl complex ion in the UV-Vis spectral region. The ground state is an orbitally non-degenerate doublet E and the MCD is a -term spectrum caused by spin-orbit coupling. Calculations of the electronic spectrum at various levels of theory indicate that differential dynamic electron correlation has a strong influence on the energies of the dipole-allowed transitions and the envelope of the MCD spectrum. The experimentally observed bands are assigned to dipole-allowed ligand-to-metal charge transfer into the 5f shell, and 5f to 6d transitions. Charge transfer excitations into the U 6d shell appear at much higher energies. The MCD-allowed transitions can be assigned via their signs of the -terms: Under O double group symmetry, E → E transitions have negative -terms whereas E → F transitions have positive -terms if the ground state g-factor is negative, as it is the case for UCl.
我们展示了对八面体UCl络合离子在紫外-可见光谱区域的磁圆二色性（MCD）光谱进行的从头算理论与实验相结合的研究。基态是轨道非简并的二重态E，且MCD是由自旋-轨道耦合引起的一项光谱。在不同理论水平下对电子光谱的计算表明，微分动态电子关联对偶极允许跃迁的能量以及MCD光谱的包络有强烈影响。实验观测到的谱带被归属为偶极允许的配体到金属的电荷转移到5f壳层，以及5f到6d的跃迁。电荷转移激发到U的6d壳层出现在高得多的能量处。MCD允许的跃迁可以通过它们的一项符号来归属：在O双群对称性下，如果基态g因子为负，如UCl的情况，E→E跃迁具有负的一项，而E→F跃迁具有正的一项。
