Geometry driven structures in Na₂₀photoemission time delays

The advent of attosecond laser pulses has enabled the observation of ultrafast electronic dynamics of matter in real-time and initiated a number of studies in this direction over the past several years [1]. The photoemission time delay studies were reported earlier on valence shells of C₆₀ near the cavity minima of emission [2]. The detection of minima in photoemission spectra of metal clusters [3] suggests possibilities of similar studies in cluster systems. In the current work, we study the photoemission quantum phases and Wigner-Smith time delays for Na₂₀ cluster in the high energy region where such minima are seen [4]. Fundamentally, these structures arise due to the diffraction experienced by the outgoing photoelectron from the cluster edge. The ground state of Na₂₀ is modelled using a jellium-based density functional method with a gradient corrected exchange-correlation functional (LB94) and its photoresponse properties are studied using the time-dependent local density approximation (TDLDA) [5].

References :

[1] R. Pazourek et al., Rev.Mod.Phys. 87, 765 (2015).

[2] M. Magrakvelidze et al., Phys. Rev. A 91, 053407 (2015).

[3] K. Jänkälä et al., Phys. Rev. Lett. 107, 183401 (2011).

[4] O. Frank and J.M. Rost, Chem. Phys. Lett. 271 367 (1997).

[5] J. Choi et al., Phys. Rev. A 95, 023404 (2017).