Models replace nucleus by model reduced physical system. reliable and sufficiently simple description of some properties of nuclei. 44 Phenomenological models – mean potential of nucleus is used, its parameters are determined from experiment. Electric quadruple moment Q: gives difference of charge distribution from spherical. Elastic scattering – intrinsic state of motion of participated particles is not changed during scattering particles are not excited or deexcited and their rest masses are not changed. Different nuclei with the same number of neutrons – isotones.
Momenta are equilibrated by electron cooling → for different masses → different velocity and frequency. The smaller studied object → the smaller wave length of studying radiation → the higher E and p of quanta (particles) of this radiation. Estimation for Rutherford model: Substituting R A = R J 10 -14 m (only quantitative estimation): tan 2.7 → 70 o also very large scattering angles. Approximate relation R = f(A) can be derived from measurements: R = r 0 A 1/3 where we obtained from measurement r 0 = 1,2(1) 10 -15 m = 1,2(2) fm (α = 1,8 fm -1 ). This shows on permanency of nuclear density.
Spin and orbital angular momenta for pair are zeroed. Some mother nuclei can decay by two different ways either by electron decay or electron capture to two different nuclei. Assumption: nuclear charge in the ground state is distributed uniformly → electric dipole momentum is zero.