Electronic structure, absorption spectra and oxidation dynamics in polyynes and dicyanopolyynes

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Femtosecond to attosecond experimental tools enable the study of ultrafast carrier dynamics.
• Understanding charge density evolution in molecules like polyynes and dicyanopolyynes is crucial for their application as atomic wires.

Purpose of the Study:

• To investigate the electronic structure and hole transfer in symmetric polyynic carbynes and dicyanopolyynes.
• To develop and apply computational methods for simulating ultrafast carrier dynamics in these molecules.

Main Methods:

• Utilized density functional theory (DFT) methods, including constrained DFT (CDFT), time-dependent DFT (TDDFT), and real-time TDDFT (RT-TDDFT).
• Developed and applied a tight-binding (TB) variant using all valence orbitals for electronic structure and charge transfer calculations.
• Incorporated Löwdin population analysis and considered zero-point motion for accurate results.

Main Results:

• Calculated electronic structure, time-dependent dipole moments, and hole transfer probabilities.
• Determined mean transfer rates and frequency content from charge and dipole moment oscillations.
• Compared computational results with available experimental data.

Conclusions:

• The study provides a comprehensive analysis of ultrafast carrier dynamics in polyynes and dicyanopolyynes.
• The developed TB variant is suitable for studying both linear and non-linear molecular systems and clusters.
• The findings contribute to the understanding of charge transport in potential molecular electronic devices.