Precision of Electric-Field Gradient Predictions by Density Functional Theory and Implications for the Nuclear Quadrupole Moment and Its Error Bar of the 111Cd 245 keV 5/2+ Level

L. A. ERRICO; K.LEJAEGHERE; J. RUNCO; S. MISHRA; M. RENTERÍA; S. COTTENIER

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2016 vol. 120 p. 23111 - 23120

1932-7447

We present ab initio calculated electric-fieldgradient tensors at Cd sites in a set of simple yet diversenoncubic metals. By combining these predictions with carefullyselected published experimental data, the nuclear quadrupolemoment of the 245 keV 5/2+ level of 111Cd is determined tobe 0.76(2) b. Knowing this quadrupole moment is importantfor time-differential perturbed angular correlation spectroscopy:decades of experimentally obtained nuclear quadrupolecoupling constants for solids can now be more reliablyconverted into electronic structure information. For nuclearphysics systematics, this is a rare opportunity to have reliablequadrupole moment information for a short-lived level that isnot accessible to regular experimental methods. Much effort isspent on the determination of a meaningful error bar, which is an aspect that gained only recently more attention in the contextof density functional theory predictions. This required assessing the numerical uncertainty in density functional theorypredictions for electric-field gradient tensors in solids. In contrast to quantum chemistry methods, these density functional theorypredictions cannot detect systematic errors. By comparing our quadrupole moment value with an independent value obtainedfrom quantum chemistry calculations and experiment, we show that systematic errors are small for the systems studied here. Yet,there are indications that density functional theory underestimates by a few percent the electric-field gradient, and thereforeoverestimates the quadrupole moment by the same amount. We point out which future work needs to be done to characterizethe possible deviations inherent to density functional theory.