The PYXAID Program for Non-Adiabatic Molecular Dynamics in Condensed Matter Systems

Area of Science:

• Computational Chemistry
• Condensed Matter Physics
• Materials Science

Background:

• Non-adiabatic molecular dynamics are crucial for understanding photoinduced processes.
• Simulating these dynamics in large systems is computationally demanding.

Purpose of the Study:

• Introduce the PYXAID program for efficient ab initio non-adiabatic molecular dynamics.
• Investigate ultrafast electron relaxation in crystalline pentacene.

Main Methods:

• Employs the classical path approximation with the fewest switches surface hopping approach.
• Utilizes ab initio calculations for systems with hundreds of atoms and thousands of electronic states.

Main Results:

• Simulated electron relaxation in crystalline pentacene occurs on a 500 fs timescale.
• The relaxation is driven by molecular lattice vibrations at 200-250 cm(-1).
• Results show excellent agreement with experimental data.

Conclusions:

• PYXAID is an efficient and flexible tool for studying photoinduced dynamics.
• The program enhances user-friendliness through its Python extension module design.
• Available under GNU GPL with source code and documentation online.