Quantum Chemistry vs Molecule Formation.

A textbook in modern physics will inform an innocent student that modern chemistry is based on the modern physics of Quantum Mechanics describing the world of atoms and molecules by a wave function $\Psi$ subject to unitary evolution in time according to Schrödinger's Equation SE. The message is that $\Psi$ contains "all there is to say" about any given system. So is modern chemistry based on Quantum Chemistry QC described by unitary evolution of wave functions. Very general and suitable for setting the stage.

The student is then informed that computation of the wave function $\Psi$ undergoing unitary evolution is very demanding because $\Psi (x,t)$ depends on a $3N$-dimensional spatial coordinate $x$ running over configuration space for a system with $N$ electrons, and also on time $t$, and so has exponential computational complexity.  QC thus can only be used with drastic reduction in space and then usually in time-independent eigenvalue form with a trivial phase factor as time dependence. 

The student thus has to accept that simulation of dynamical formation of molecules with state-of-the-art QC software is very demanding. In unitary evolution the environment has to be included to act as a reservoir of excess energy released during the molecule formation. This may set down the enthusiasm since is presumably what an eager student would like to learn about. 

RealQM based on a different SE in 3 space dimensions appears to open new possibilities for simulation of the formation of molecules in the form of a time-stepping 3-line-code with linear computational complexity where excess energy is handled by parabolic relaxation.  Check out this article and run 3-line codes for formation of the basic molecules $H_2$ and $He_+H$ with an opening to large molecules.