CONICET | Buscador de Institutos y Recursos Humanos

Nuclear methods (such as Mössbauer spectroscopy, nuclear magnetic and nuclear quadrupole resonance, or γ-γ perturbed-angular correlations [TDPAC], among others) have been extensively applied to study materials to elucidate the (sub)nanoscopic scale environmentof impurities or constituent atoms of solids. These techniques are based on the observation ofthe coupling between nuclear moments and extra-nuclear fields. The information provided isgiven as a product of a nuclear and an extra-nuclear quantity. In the case of electric-quadrupoleinteractions, the nuclear quantity is the nuclear quadrupole moment (Q), characteristic of agiven nuclear state with spin I, which interacts with the electric-field gradient (EFG) at thenuclear position. This product is proportional to the the so-called quadrupole coupling constantfrequency ν_Q.All the information that ν_Q can provide about the system under study could be obtainedby confrontation with an accurate prediction of the EFG, such as those obtained with ab initioelectronic-structure calculations. Of course, accurate values of the nuclear-quadrupolemoments Q are essential for a correct comparison between the experimentally determinedEFG and its theoretical prediction. For this reason, the knowledge of reliable Q values is ofgreat importance in atomic, molecular, and condensed-matter physics, besides the directinterest in nuclear physics, where the determination of Q values can be used to check nuclearmodels. However, for many important probe nuclei, the Q values are not known or are knownwith limited accuracy and/or limited precision and their determination is still an open field ofresearch. This is the case of the (111In→)111Cd isotope. This isotope is the most frequently usedtracer in TDPAC experiments and has been largely used to study semiconductor physics.Although the importance of this isotope, the nuclear quadrupole moment of the sensitive state(the 5/2+ 245 keV excited state) is known with limited precision (relative error of 17%).In this work we present an ab initio determination of the nuclear-quadrupole moment ofthe I=5/2+ excited state of 111Cd. This determination was obtained using the commonprocedure of correlating ab initio calculated EFGs and experimentally determined quadrupolecoupling constants. Our Q value [Q(5/2+, 111Cd) = 0.83(4) b] is in excellent agreement withthose reported in the literature [Q=0.83(13) b] but is obtained with largely better precision.

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