17 research outputs found
Photoionization of few electron systems with a hybrid Coupled Channels approach
We present the hybrid anti-symmetrized coupled channels method for the
calculation of fully differential photo-electron spectra of multi-electron
atoms and small molecules interacting with strong laser fields. The method
unites quantum chemical few-body electronic structure with strong-field
dynamics by solving the time dependent Schr\"odinger equation in a fully
anti-symmetrized basis composed of multi-electron states from quantum chemistry
and a one-electron numerical basis. Photoelectron spectra are obtained via the
time dependent surface flux (tSURFF) method. Performance and accuracy of the
approach are demonstrated for spectra from the helium and berryllium atoms and
the hydrogen molecule in linearly polarized laser fields at wavelength from 21
nm to 400 nm. At long wavelengths, helium and the hydrogen molecule at
equilibrium inter-nuclear distance can be approximated as single channel
systems whereas beryllium needs a multi-channel description
Photo-Ionization of Noble Gases
We present here an application of the recently developed hybrid coupled channels approach to study photo-ionization of noble gas atoms: Neon and Argon. We first compute multi-photon ionization rates and cross-sections for these inert gas atoms with our approach and compare them with reliable data available from R-matrix Floquet theory. The good agreement between coupled channels and R-matrix Floquet theory show that our method treats multi-electron systems on par with the well established R-matrix theory. We then apply the time dependent surface flux (tSURFF) method with our approach to compute total and angle resolved photo-electron spectra from Argon with linearly and circularly polarized 12 nm wavelength laser fields, a typical wavelength available from Free Electron Lasers (FELs