Generation of electronic flux during the femtosecond π/2 laser pulse tailored to induce adiabatic attosecond charge migration in HCCI+

Adiabatic attosecond charge migration (AACM) in a linear molecule or cation such as HCCI+ means that the system has been prepared in a superposition state e.g. of the electronic ground and first excited states, corresponding to a surplus of density of valence electrons on one side which is compensated by a deficit of electron density on the other side. Subsequently, the surplus and deficit interchange such that the surplus of electron density migrates from its initial site to the opposite site, and back, periodically. The migration proceeds adiabatically on the attosecond time domain, i.e. without diabatic transitions between eigenstates. It is associated with electronic flux that mediates the charge migration. Here, we tailor a femtosecond pi/2 laser pulse such that it induces AACM in the oriented model HCCI+, with maximum electronic flux. The case study shows that the flux is generated already during the laser pulse, suggesting equivalent processes during laser initiations of AACM in many or all other systems. The results are obtained by means of quantum dynamics simulation.