Local control theory using trajectory surface hopping and linear-response time-dependent density functional theory.

Area of Science:

• Quantum Chemistry
• Theoretical Chemistry
• Computational Physics

Background:

• Accurate modeling of molecular photoexcitation is crucial for understanding chemical dynamics.
• Controlling electronic state population transfer requires precise external field manipulation.
• Nonadiabatic molecular dynamics and time-dependent density functional theory offer pathways for such studies.

Purpose of the Study:

• To implement local control theory with nonadiabatic molecular dynamics for photoexcitation control.
• To demonstrate efficient on-the-fly pulse generation for population transfer.
• To analyze the generated pulse for insights into molecular photophysics.

Main Methods:

• Linear-response time-dependent density functional theory (LR-TDDFT).
• Nonadiabatic molecular dynamics with trajectory surface hopping.
• Local control theory for optimal laser pulse generation.

Main Results:

• Successful generation of an on-the-fly control pulse for lithium fluoride photoexcitation.
• Demonstrated efficient control over population transfer between electronic states.
• Identified key frequencies related to potential energy curves and state energy differences.

Conclusions:

• The implemented method provides an efficient route for controlling molecular photoexcitation.
• Analysis of control pulses offers insights into the underlying photophysical processes.
• The study discusses limitations of the trajectory surface hopping approach.