Amyand David Buckingham. 28 January 1930—4 February 2021

David Buckingham was a chemical physicist and theoretical chemist who made fundamental contributions to the understanding of optical, electric and magnetic properties of molecules. Born in Australia, he was an undergraduate at the University of Sydney and the first PhD research student of John Pople (FRS 1961) at Cambridge, and there he made significant advances in the theory of intermolecular forces and nonlinear optics. He then moved to Oxford, where he and his group performed the first direct measurement of a molecular electric quadrupole moment. He was elected to the first chair of theoretical chemistry at the University of Bristol, where he wrote a particularly influential article on molecular moments, higher-order polarizabilities and intermolecular forces. His next appointment was at the University of Cambridge as the first holder of the 1968 Chair of Chemistry, and he was head of a distinguished department of theoretical chemistry for 28 years. With colleagues he pioneered experiment and theory on vibrational optical activity and developed a powerful model to predict the structures of weakly-bound molecules. A man of broad interests and achievements, he played first class cricket in the 1950s.

Calculation of the Electric Quadrupole Moment of 6Li and 7Li in Shell Model and Cluster Model

In this paper, we have investigated electric quadrupole moment of (_^6)Li and (_^7)Li in both shell model and cluster model. In shell model, the nuclei (_^6)Li and (_^7)Li can be modeled as one core plus nucleons. Nucleons outside the closed shell can be considered as a two- and three-particle system. In cluster structure, we have selected alpha clusters and triton or deuteron in interaction with alpha cluster ((_^7)Li and (_^6)Li involving α+(_^3)H and α+(_^2)H, respectively). By solving Schrödinger equation and using suitable potential for interaction between particles by applying Nikiforov-Uvarov method, potential coefficients have been computed. Then, we have calculated the energy and wave function for nuclei(_^6)Li and (_^7)Li and compared the results obtained with experimental results. By having the wave function, we can obtain the quadrupole moment. These values are compared with predictions from shell-model and cluster-model calculations. Although the difference between them is small, the electric quadrupole moment results in the cluster model are in good agreement with experimental results. Keywords: Electric quadrupole moment, Shell-model, Cluster-model, Li isotopes, Non-relativistic equation.

The Radiative Δ(1600) → γN Decay in the Light-Cone QCD Sum Rules

Within the framework of the light-cone QCD sum rules method (LCSR’s), the radiative Δ(1600)→γN decay is studied. In particular, the magnetic dipole moment GM1(0) and the electric quadrupole moment GE1(0) are estimated. We also calculate the ratio REM=−GE1(0)GM1(0) and the decay rate. The predicted multipole moments and the decay rate strongly agree with the existing experimental results as well as with the other available phenomenological approaches.

Ground and excited state characteristics of the nuclei with A = 6

The binding energy, the root-mean-square radius, the magnetic dipole moment, the electric quadrupole moment, and the moment of inertia of the nucleus 6Li are calculated by applying different models. The translation invariant shell model is applied to calculate the binding energy, the root-mean-square radius, and the magnetic dipole moment by using two- and three-body interactions. Also, the spectra of the nuclei with A = 6 are calculated by using the translation-invariant shell model. Moreover, the ft-value of the allowed transition: 6He(Jπ=0+;T=1)β- → 6Li(Jπ=1+;T'=1) is also calculated. Furthermore, the concept of the single-particle Schrodinger fluid for axially symmetric deformed nuclei is applied to calculate the moment of inertia of 6Li. Also, we calculated the magnetic dipole moment and the electric quadrupole moment of the nucleus 6Li in this case of axially symmetric shape. Moreover, the nuclear superfluidity model is applied to calculate the moment of inertia of 6Li, based on a single-particle deformed anisotropic oscillator potential added to it a spin-orbit term and a term proportional to the square of the orbital angular momentum, as usual in this case. The single-particle wave functions obtained in this case are used to calculate the magnetic dipole moment and the electric quadrupole moment of 6Li.

Comment on: “Some quantum aspects of a particle with electric quadrupole moment interacting with an electric field subject to confining potentials”

We analyze the results obtained from a model consisting of the interaction between the electric quadrupole moment of a moving particle and an electric field. We argue that the system does not support bound states because the motion along the [Formula: see text] axis is unbounded. It is shown that the author obtains a wrong bound-state spectrum for the motion in the [Formula: see text] plane and that the existence of allowed cyclotron frequencies is an artifact of the approach.