PULSE-PySpawn: Time-Resolved Transient Absorption Simulation through Ab Initio Multiple Spawning Dynamics with...

Area of Science:

• Computational Chemistry
• Spectroscopy
• Quantum Dynamics

Background:

• Time-resolved transient absorption spectroscopy is crucial for understanding ultrafast molecular processes.
• Accurate modeling requires capturing non-adiabatic dynamics and laser-matter interactions.

Purpose of the Study:

• To develop a novel computational workflow for simulating time-resolved transient absorption spectra.
• To integrate laser field effects and pump-probe sequences into dynamics simulations.
• To enable reconstruction of spectroscopic signals from theoretical trajectories.

Main Methods:

• Propagating non-adiabatic dynamics using ab initio multiple spawning.
• Explicitly including laser fields in the molecular Hamiltonian.
• Developing a flexible workflow for varied probe energies and time delays.
• Integrating the workflow into the open-source PySpawn software.

Main Results:

• The workflow successfully models the effects of pump and probe pulses on molecular systems.
• Spectroscopic signals can be reconstructed from a single set of simulated trajectories.
• The method was validated by simulating the transient absorption spectrum of azomethane.

Conclusions:

• The developed workflow provides a powerful tool for interpreting time-resolved spectroscopic experiments.
• This method enhances the simulation of non-adiabatic dynamics under realistic experimental conditions.
• The integration with PySpawn increases accessibility and usability for researchers.