Download or read book Molecular Propagation through Electron Energy Level Crossings written by George Allan Hagedorn and published by American Mathematical Soc.. This book was released on 1994 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: The principal results of this paper involve the extension of the time-dependent Born-Oppenheimer approximation to accommodate the propagation of nuclei through generic, minimal multiplicity electron energy level crossings. The Born-Oppenheimer approximation breaks down at electron energy level crossings, which are prevalent in molecular systems. We classify generic, minimal multiplicity level crossings and derives a normal form for the electron Hamiltonian near each type of crossing. We then extend the time-dependent Born-Oppenheimer approximation to accommodate the propagation of nuclei through each type of electron energy level crossing.