Spectral anlaysis of correlated wave functions for attosecond photoionization processes

The wave functions are obtained by integrating the time-dependent
Schrödinger equation on a finite-element discrete variable representation basis (FEDVR) [1], starting from either the ground or the first excited 1S state of helium. The spectral components are computed with: an extraction method based on exterior complex scaling [3], projection onto fully correlated multi-channel scattering states obtained with the B-spline K-matrix method [4], and projection onto products of hydrogenic bound and continuum states. Excellent agreement between the spectra obtained with the first two methods is found.

This result shows that correlated atomic states obtained in the B-splines basis can be converted with high accuracy to the FEDVR representation, thus giving access to efficient way to monitor the population of continuum and doubly excited states during the time evolution of a ionizing wavepacket as it interacts with an external laser field.

References
[1] J. Feist et al., Phys. Rev. A 77, 043420 (2008).
[2] L. Argenti and E. Lindroth, Phys. Rev. Lett. 105, 053002 (2010).
[3] A. Palacios, C. W. McCurdy and T. N. Rescigno, Phys. Rev. A 76, 043420 (2007)
[4] L. Argenti and R. Moccia, J. Phys. B: At. Mol. Opt. Phys. 40, 3655 (2007)