# Chapter 4: Molecular Hamiltonians

"The best that most of us can hope to achieve in physics is simply to misunderstand at a deeper level."

– Wolfgang Pauli

At the end of Wolfgang Pauli's 1946 Nobel lecture [Pauli] he states:

*"I may express my critical opinion, that a correct theory should neither lead to infinite zero-point energies nor to infinite zero charges, that it should not use mathematical tricks to subtract infinities or singularities, nor should it invent a hypothetical world which is only a mathematical fiction before it is able to formulate the correct interpretation of the actual world of physics."*

The concepts in this chapter have a mathematical formulation and do not have a physical or chemical reality. In other words, there are standard approximations used that allow the...