Hierarchy of effective modes for the dynamics through conical intersections in macrosystems

Area of Science:

• Quantum Chemistry
• Theoretical Chemistry
• Chemical Physics

Background:

• Effective-mode theory simplifies complex molecular dynamics.
• Conical intersections are crucial for non-adiabatic processes.
• Macrosystems present challenges due to numerous nuclear degrees of freedom.

Purpose of the Study:

• To extend effective-mode theory for simulating short-time dynamics in macrosystems with conical intersections.
• To develop an iterative scheme for constructing a hierarchy of effective modes.
• To enable accurate calculation of low-resolution spectra and dynamics over extended time scales.

Main Methods:

• Decomposition of macrosystems into system and environment parts.
• Iterative construction of additional triplets of effective modes.
• Application of the extended effective-mode theory to numerical examples.

Main Results:

• The extended theory accurately captures short-time dynamics and low-resolution spectra using a minimal set of effective modes.
• The iterative scheme allows for systematic improvement of accuracy by including more effective mode triplets.
• Simulations with increasing numbers of effective modes predict dynamics for progressively longer times and yield more resolved spectra.

Conclusions:

• The proposed iterative hierarchy of effective modes provides a powerful extension of the effective-mode theory.
• This approach enables accurate and efficient simulation of complex quantum dynamics in large molecular systems.
• The method is versatile for calculating both spectral properties and time-dependent dynamics.