Non-equilibrium x-ray spectroscopy using direct quantum dynamics.

Area of Science:

• Physical Chemistry
• Quantum Mechanics
• Spectroscopy

Background:

• Advanced X-ray techniques offer high resolution for diverse samples.
• Complex X-ray spectra necessitate theoretical studies for molecular interpretation.
• Current methods often require extensive precomputation of potential energy surfaces.

Purpose of the Study:

• To develop an efficient quantum dynamics simulation approach for X-ray spectroscopy.
• To enable a fully quantum description of X-ray spectra without precomputed potential energy surfaces.
• To apply the method to challenging dynamical processes in molecular systems.

Main Methods:

• On-the-fly quantum dynamics simulations utilizing a Gaussian basis set.
• Direct simulation of X-ray spectra from quantum dynamics trajectories.
• Application to core-hole lifetime dynamics and molecular dissociation.

Main Results:

• Accurate simulation of X-ray spectra is achieved without multidimensional potential energy surfaces.
• The method successfully models the core-hole lifetime dynamics of water monomer.
• Simulations of $$ dissociation align well with experimental data.

Conclusions:

• The developed method provides a computationally efficient and accurate approach for simulating X-ray spectroscopy.
• This technique facilitates the link between experimental observables and molecular dynamics.
• The approach is scalable for application to larger and more complex molecular systems.