User:PhaseChanger/sandbox

Molecular Mechanics Type = empirical Advantages= Is a classical physics model, so has no difficult equations. Disadvantages= Doesn't describe non-bonding interactions well. Isn't quantum mechanical. Best for = proteins Hartree-Fock Type = ab-initio Advantages = Easy to use. Was the first ab-initio method to work, unlike Hartree product which violated the Pauli principle Disadvantages = only accounts for 99% of energy Best for = being a start point, not actual calculations. DFT Type = semi-empirical/ DFT Advantages = density rather than wavefunctions Disadvantages = Weak interactions are poorly described, It's not systematicall improveable, Loosely bound electrons pose a problem Best for = Small-ish molecules Truncated CI Type = ab-initio (HF) + post-HF (also ab-initio) Advantages = Simplest. Attempts to recover some of the 1% Disadvantages = size-inconstant and not size extensive Best for = small molecules Computational effort=over 9000 lol MP fits in here? Type = Post HF Advantages= Fastest out of CC and CI, can calculate correlation energy better too Disadvantages= Convergance questionable CC Type = ab-initio (HF) + post-HF (also ab-initio) Advantages = truncated CC is size consistant and size extensive Disadvantages = Best for = Small molecules. Computational effort = huge Full CI Type = ab-initio + post-HF (also ab-initio) Advantages = Exact solution as solving Schrodinger equation Disadvantages = includes all excitation determinants Best for = tiny molecules (homnuclear diatomics) Computational effort = huge