Molecular propagation through electron energy level crossings

This largely self-contained book provides a thorough discussion of the mathematics of molecular dynamics and fills a gap in the theoretical knowledge of the subject.

Most knowledge of molecular propagation is derived from the time-dependent Born-Oppenheimer approximation.

This approximation breaks down at electron energy level crossings, which are prevalent in molecular systems.

Hagedorn classifies generic, minimal multiplicity level crossings and derives a normal form for the electron Hamiltonian near each type of crossing.

He then extends the time-dependent Born-Oppenheimer approximation to accommodate the propagation of nuclei through each type of electron energy level crossing.