Dynamic Spin-Orbit Effects in Spontaneous E1 Transitions

Abstract

Despite undoubtedly many impressing successes our ability to comprehensively understand and explain nature in all its facets will remain limited as long as we have to resort to simplifying models which inherently can only deliver what has been built into. Despite their shortcomings, however, these models often have proven beneficial as guidelines and eye-openers to deeper insight and ensuing progress. One of these simplifications is the notion that dynamic features with strongly differing time scales can be treated independently. Presumably the most successful example of these adiabatic approximations is the one devised by Born and Oppenheimer¹. Extended to the adiabatic approximation it describes the expectation values of diatomic molecules very accurately, except for the vicinity of curve-crossings. In atomic physics the notion of a priori fine-structure eigenstates was very successful in interpreting spectra. This success supported the perception that quantum systems exist in eigenstates in the first place. As a consequence, transient phenomena such as quantum interference effects were explained by a superposition of eigenstates. In this article, however, we offer an alternative approach and explanation. We will demonstrate that by rigorously solving the time-dependent Schroedinger equation in interaction representation with spin-orbit and electric dipole interaction treated simultaneously finer details of the dynamics of spin-orbit coupling in radiatively decaying states can be described.