To date, true ab initio models describing the complete fission process are not possible. Computational theories based on Hartree–Fock or density-functional theory approaches have been developed, however computational complexity makes it difficult to reproduce the full behaviour. The semi-classical liquid-drop model provides a primarily qualitative description of the phenomenology by treating the nucleus as a classical drop of liquid to which quantum corrections can be applied, which provides a useful conceptual picture that matches in part with experimental data, but ignores much of the quantum nature of the system and fails at more rigorous predictions.