## Zur quantentheorie der Molekeln [Offprint from] Annalen der Physik 84, No. 20, 1927

Leipzig: Barth, 1927. 1st Edition. OFFPRINT. FIRST EDITION IN ORIGINAL WRAPS OF THE 1927 BORN & OPPENHEIMER APPROXIMATION, ONE OF THE MOST IMPORTANT & FUNDAMENTAL APPROXIMATIONS IN MOLECULAR QUANTUM MECHANICS. The Born-Oppenheimer approximation is a simplification that breaks the wavefunction of a molecule into its electronic and nuclear (vibrational, rotational)..... More