Nuclear Droplets Research Articles

The nuclear droplet model for arbitrary shapes

The Droplet Model of masses and density distributions, introduced in Ref. [1] for spherical configurations, is generalized to arbitrary shapes. Equations in closed form are given for the neutron and proton density nonuniformities induced by the electric forces, and also for the dependence of the neutron skin thickness on position on the nuclear surface. The formulas for the corrections to the nuclear energy associated with these effects are derived and this leads to a Droplet Model atomic mass formula which is presented with a preliminary set of coefficients adjusted to nuclear ground state masses and fission barriers.

A semiclassical treatment of the dynamic ellipsoidal shapes in nuclei

In the dynamics of collective vibration and rotation, nuclei in the deformed and transitional regions pass through ellipsoidal shapes of continuously varying deformation. As a first step towards working out these collective dynamics, exact classical expressions have been obtained for the surface, curvature and Coulomb energies of a nuclear droplet having an ellipsoidal shape. The kinetic energy corresponding to surface vibration and rotation has also been calculated using the classical picture of the irrotational motion of an incompressible fluid confined by an ellipsoidal boundary. The shell and pairing corrections to the nuclear energy are obtained, following a slightly modified version of Strutinsky's prescription. The shellmodel potential used for this purpose has a harmonic-oscillator shape with equipotential surfaces having the same eccentricities as the ellipsoidal nuclear droplet. The collective Hamiltonian has then been taken to be the sum of the kinetic energy, and the surface, curvature and Coulomb energies together with the shell and pairing corrections. This Hamiltonian has then been quantized, as done by Bohr in his pioneering work on the collective model. A simple numerical method for solving the resultant Schrodinger equation has been worked out.

Guanidine Nitrate and the Allium Test

SUMMARYObservations have been made on the effects of guanidine nitrate by means of the Allium test, together with observations on its overall physiological activity. This substance has been found to be lethal and toxic in high concentrations, and in low concentrations to produce bends, curls and lateral roots in Allium. Cytologically, guanidine produces extreme stickyness, leeding to anaphase bridges and blocked metaphases. The frequency of mitosis is reduced by all but the lowest concentrations.Restitution and polymorphic figures are produced together with nuclear shrinkage and droplet extrusion, by high concentrations. Such droplets are found to be feulgen negative. Its thermodynamic activity has been determined as 0.0001, thus showing its action to be specific and chemical.