A semiclassical hybrid approach to many particle quantum dynamics

Area of Science:

• Computational Chemistry
• Quantum Dynamics
• Theoretical Physics

Background:

• Accurate simulation of many-particle quantum dynamics is computationally intensive.
• Existing semiclassical methods like Herman-Kluk and thawed Gaussian approximations have limitations.
• Mixed quantum-classical approaches are needed for complex systems.

Purpose of the Study:

• To develop a novel hybrid semiclassical approach for mixed quantum-classical dynamics.
• To reduce the numerical effort required for simulating many-particle systems.
• To apply and validate the new method on a benchmark atom-diatomic collision model.

Main Methods:

• Analytically derived correlated approach combining Herman-Kluk and approximate fixed phase space dynamics.
• Hybrid method treats a fraction of degrees of freedom with Herman-Kluk and others with fixed variables.
• Application to the Secrest-Johnson model for atom-diatomic collisions.

Main Results:

• Promising results obtained for the Secrest-Johnson model.
• Achieved quantum-like correlation functions and scattering probabilities.
• Significantly reduced numerical effort compared to the full Herman-Kluk method.
• Method allows for a posteriori determination of harmonic nature of degrees of freedom.

Conclusions:

• The hybrid semiclassical approach is efficient and accurate for mixed quantum-classical dynamics.
• It provides a viable alternative to full semiclassical methods for complex systems.
• The method demonstrates potential for broader applications in chemical dynamics.