Theoretical models edge closer to explaining how photoionization is affected by many-body interactions.
L. R. Moore et al., Phys. Rev. A (2011)
In 2010, experimentalists made a curious discovery when they ionized neon atoms with short, intense pulses of ultraviolet light. The time it took for an electron in the orbital of the atom to be emitted was 21 attoseconds longer than that of an -orbital electron. The discrepancy was a sign that electron correlations play a role. Initial theoretical calculations of the delay confirmed the existence of a time difference between the emission processes, but the theoretical time delay was three times shorter than the experimental delay.
Now, Laura Moore and colleagues at Queen’s University Belfast, UK, have approached the problem using a time-dependent description of the complex laser-atom interaction. Their method, which is presented in Physical Review A, attempts to model the system by following the same time evolution of the photo-excited electrons as in the experiment.
The calculated time delays are found to be about 10 attoseconds, once again, half those found in experiment. The discrepancy between theory and experiment enlivens the investigation, but is not surprising in the early stage of exploration. According to the authors, theoretical calculations can be improved by accounting for the full complexity of the many-electron motion induced by the ultraviolet light. – Jessica Thomas
Experiments using a replica model of the mouth and throat could help in designing safe-to-eat drinks, foods, and drugs for those who have trouble swallowing.
The Dark Energy Survey has completed a six-year observing run that will put our cosmology models to the most stringent test yet, as reported at the American Astronomical Society winter meeting.
Biophysicist Jennifer Ross hopes to find the rules that govern how cells restructure and self-repair, with the goal of creating new materials that do the same thing.
Prize recognizes Arthur Ashkin, Gérard Mourou, and Donna Strickland for developing laser tools that have led to new biophysics experiments and medical technologies.
