Formulation of non-adiabatic molecular dynamics triggered by core ionization

Kota Hanasaki, Oriol Vendrell, Sang-Kil Son, Ludger Inhester, Yajiang Hao, and Robin Santra

[BibTeX]https://www.femto12.org

High-intensity ultrafast laser pulses in vacuum-ultraviolet (VUV) to X-ray regime generated by Free-Electron Laser offer unique opportunity to probe molecular dynamics, enabling real-time tracking of non-adiabatic dynamics over a wide range of potential energy surfaces (PES). Molecular decay dynamics in these experiments is distinct from what is covered by conventional molecular dynamics (MD) in that it include electronic decay processes (Auger and fluorescence) that cause transitions far beyond the typical energy scale in standard MD. We hence develop a new molecular calculation toolkit XMOLECULE and a new non-adiabatic MD scheme. XMOLECULE realizes Hartree-Fock-Slater (HFS) calculation of an arbitrary molecular electronic configuration based on core-hole adapted numerical atomic orbitals provided by XATOM toolkit. Based on this fast on-the-fly calculation, we propose a new non-adiabatic calculation scheme which extends the surface hopping scheme by combining high-energy electronic transitions as "large hop" and lower-energy non-adiabatic transitions as "small hop".

Tags: XMOLECULE, non-adiabatic, molecular dynamics, MD, surface hopping, SH, CFEL, DESY