Closed-orbit theory for the photodetachment rate in a static magnetic field transversely superimposed to an oscillatory electric field
Abstract
The closed-orbit theory is used for the study of the photodetachment rate of electrons from single-charged anions in presence of a homogeneous magnetic field that is perpendicular to a time-dependent electric field. The photodetachment process in the near-threshold region is achieved by a weak laser field. We describe in detail the semiclassical method to derive the general formula for the instant photodetachment rate in time-dependent systems. We find that the photodetachment rate is affected by the presence of the static magnetic field since, within the semiclassical picture, it contributes to fold back the electron trajectories back to their emission position: generating closed orbits. For weak magnetic fields, however, the number of closed orbits does not change, then the modulation of the photodetachment rate is virtually unaffected when it is compared to the case with no magnetic field. On the contrary, the modulation is clearly distinctive and complicated for strong magnetic field intensities due to the contribution of a larger number of closed orbits. Despite we provide general formulas, numerical experiments and discussions are focused on the emission of electrons as $s$-waves and $p_z$-waves.
