The Photoionization Time in π-Conjugated Molecular Systems

Area of Science:

• Physical Chemistry
• Quantum Mechanics
• Molecular Spectroscopy

Background:

• Understanding molecular photoionization dynamics is crucial for various fields, including attosecond science and chemical reaction dynamics.
• Ethylene (C2H4) serves as a fundamental model system for studying π-conjugated molecular electronic behavior.

Purpose of the Study:

• To calculate the photoionization time of ethylene (C2H4) as a representative π-conjugated molecular system.
• To compare theoretical calculations using the Wigner phase delay with experimental energy-streaking measurements.

Main Methods:

• Analytical calculation of photoionization time employing the Wigner phase delay.
• Comparison of theoretical results with experimental data obtained from energy-streaking measurements.

Main Results:

• The photoionization time averaged over nuclear configurations shows good agreement between theoretical calculations and experimental measurements.
• Significant differences were observed in the dependence of ionization time on nuclear configuration between the Wigner phase delay method and energy-streaking experiments.
• Interference effects between ionization pathways are highly sensitive to molecular geometry and electron energy, potentially causing qualitative changes in ionization times.

Conclusions:

• The Wigner phase delay provides a valuable theoretical tool for modeling photoionization dynamics in π-conjugated systems like ethylene.
• Molecular geometry plays a critical role in photoionization, influencing interference patterns and leading to distinct ionization time behaviors.
• Further investigation into the interplay of molecular geometry, electron energy, and ionization pathways is necessary for a comprehensive understanding of photoionization dynamics.