BetheWeizsäcker
Bethe–Weizsäcker refers to the semi-empirical mass formula (SEMF) for atomic nuclei, developed in 1935 by Hans Bethe and Carl Friedrich von Weizsäcker. It provides a simple macroscopic estimate of the binding energy and thus the mass of a nucleus with mass number A and atomic number Z, based on a liquid-drop analogy and fitted to experimental masses. The formula captures general trends in nuclear binding and explains why certain isotopes are more stable than others.
The commonly used form for the binding energy B is B(A,Z) = a_v A - a_s A^{2/3} - a_c
Applications include explaining the valley of stability, estimating nuclear masses and decay energetics, and guiding nucleosynthesis