Liquid drop model as a simple parametrization of binding energies

A popular and physically intuitive model which can be used to parametrize the experimental binding energies as function of \( A \), is the so-called the liquid drop model. The ansatz is based on the following expression $$ BE(N,Z) = a_1A-a_2A^{2/3}-a_3\frac{Z^2}{A^{1/3}}-a_4\frac{(N-Z)^2}{A}, $$ where \( A \) stands for the number of nucleons and the $a_i$s are parameters which are determined by a fit to the experimental data.