Ultrafast Charge Migration in XUV Photoexcited Phenylalanine: A First-Principles Study Based on Real-Time...

Area of Science:

• * Attoscience and molecular dynamics
• * Quantum mechanics and electronic structure theory

Background:

• * Ultrafast charge migration on femtosecond timescales governs molecular relaxation pathways.
• * Accurate theoretical models require atomistic detail, electronic correlations, and ionization channel considerations.

Purpose of the Study:

• * To develop and apply a first-principles quantum theory for ultrafast charge migration.
• * To incorporate atomistic details, electronic correlations, and ionization effects into the theory.

Main Methods:

• * Developed a first-principles nonequilibrium Green's function (NEGF) method.
• * Applied the NEGF method to photoexcited phenylalanine using attosecond XUV pulses.

Main Results:

• * Dynamical correlations are essential for quantitative agreement with experimental data.
• * Successfully captured transient oscillations (0.15, 0.30 PHz) in hole density.
• * Observed suppression of initial oscillations and emergence of a new 0.25 PHz oscillation after 14 fs.

Conclusions:

• * The proposed NEGF method accurately describes ultrafast charge migration.
• * Highlights the critical role of dynamical correlations in attosecond molecular dynamics.