Photodetachment of hydrogen negative ions in bichromatic oscillating electric fields

摘要

The photodetachment of a hydrogen negative ion in the bichromatic oscillating electric field is investigated using the time-dependent closed orbit theory. The photodetachment cross section is specifically calculated in the bichromatic oscillating electric field with a 1:2 frequency ratio and various phase differences. It is found that the oscillatory structure appears in the photodetachment cross section, which depends sensitively on the strength and the phase difference of the bichromatic oscillating electric field. The time-dependent photodetachment cross section is nearly unaffected by a weak bichromatic oscillating electric field. However, with the increase of the oscillating electric field strength, four different types of the detached electron’s closed orbits are identified, which makes the photodetachment cross section oscillate in a much more complicated way. In addition, the influence of the phase difference in the bichromatic oscillating electric field on the photodetachment cross section is also investigated quantitatively. The formula we put forward for the time-dependent photodetachment cross section is universal and can be used to calculate the cross section for other frequency ratios in the bichromatic oscillating electric field. On account of its generality, our work provides a clear and intuitive picture for the photodetachment processes of a negative ion in the bichromatic oscillating electric field, and may guide future experimental research on the photodetachment dynamics in the oscillating electric field.