XChem Code

XChem package compiles a set of computational tools able to provide a full quantum mechanical
description of molecular ionization in the time domain by including both electronic and nuclear
degrees of freedom. The used approach has provided reliable predictions and has opened the way to
new applications in emerging scientific disciplines, as attochemistry, single molecule imaging,
coherent attosecond control of chemical reactions, etc

Xchem can compute

• The Close Coupling Matrix (CCM) for a user-defined set of ionization channels (each
  defined as an ionized molecular state coupled to electrons of given angular momenta) and
  including short range states relevant to the problem at hand.
• Scattering states and scattering phases by asymptotic fitting to the analytical solution.
• (Partial) photoionization cross sections within perturbation theory.
• Lifetime and character of resonances embedded in the molecular continuum, either via
  analysis of the cross section or via inclusion of a complex absorbing potential in the CCM
  yielding complex eigen-energies.
• The electron dynamics during and after ionization, caused by and probed with ultrashort
  laser pulses, by solving the time dependent Schrödinger Equation using the CCM.
• The electron dynamics during and after ionization, caused by and probed with ultrashort
  laser pulses, by solving the time dependent Schrödinger Equation using the CCM.

Xchem can be used for

• The theoretical study of ultrafast processes in pump-probe experimental method, such as
  Attosecond Transient Absorption Spectroscopy (ATAS) and Reconstruction of Attosecond
  Beatings by Interference of Two-Photon Transitions (RABBITT).
• The investigation of photoionization of complex molecules close to threshold, where
  electron correlation effects may dramatically affect the (partial) photoionization cross
  section.
• The study of ionization processes intrinsically dependent on electron correlation, like
  Autoionization and Auger Decay.
• The computation of potential energy surfaces for the investigation of molecular dynamics
  during and after fast photoionization events.