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A one-dimensional analog that reflects many of the features of the many-body Dirac equation is considered. The model can be solved numerically using a convenient finite basis discrete variable representation. Both an (unbound) harmonic oscillator potential and a (bound) inverse Gaussian one-particle potential are discussed for interacting particles. In a second thread in the paper, the mass term is neglected in the model many-body Dirac equation, and it is shown that the original equation, which has 2N coupled components for N particles can then be reduced to 2N decoupled one-component equations, which can be solved “analytically” for arbitrary many particles interacting through central two-body potentials. [ABSTRACT FROM AUTHOR]

Relativistic density functional theory (ZORA-PBE, COSMO solvation) is used to address the title question, based on comparison with recent experimental data (1). Structural data (bond lengths), vibrational frequencies, and 17O NMR chemical shifts are used to prove that [NpO4(OH)2]3– is the predominant species in high-ionic-strength alkaline solutions of NpVII. Neptunium(VII) complexes have stronger bonds than their formally isoelectronic uranium(VI) analogues. The experimentally observed 300 ppm shift in 17O chemical shifts between the known [UO2(OH)4]2– and NpVII solution is shown to be partly a function of the central metal (NpVII vs. UVI) and not of the coordination environment (tetraoxo vs. dioxo). Comparing, for a given An (UVI or NpVII), actinyl complexes [AnO2X4]2–/1–, X = Cl, F, OH, a decreasing strength of the axial actinyl bond is observed that is traced to electronic factors (equatorial π-competition). [ABSTRACT FROM AUTHOR]

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Electric field gradients at the nuclei of gallim and indium are determined by finite field calculations of the atomic energies as functions of the nuclear quadrupole moments. The four-component Dirac–Coulomb–Gaunt Hamiltonian serves as framework, and all electrons are correlated by Fock-space coupled cluster with single and double excitations or by single reference coupled cluster with approximate triples. Large, converged basis sets (e.g., 28s24p20d13f5g4h for In) and virtual spaces are used. Together with experimental nuclear quadrupole coupling constants, known with high precision, the calculated electric field gradients yield the nuclear quadrupole moments. For 69Ga, we get Q = 174(3) mb, in agreement with the earlier 171(2) mb obtained from molecular calculations. The 115In moment is Q = 772(5) mb, considerably lower than the previously accepted 810 mb, and in good agreement with the recent molecular value of 770(8) mb. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Chemistry is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)