Dipole switching in large molecules described by explicitly time-dependent configuration interaction.

Area of Science:

• Computational chemistry
• Quantum dynamics
• Molecular electronics

Background:

• Investigating laser-induced electronic excitation in molecular systems is crucial for developing molecular devices.
• Understanding the influence of molecular size on excitation selectivity is key for precise control.

Purpose of the Study:

• To simulate laser-driven charge transfer in Li-(Ph)(n)-CN molecules (n=1,2,3) to assess excitation selectivity.
• To explore how molecular size affects the controllability of ultrashort laser-induced electronic excitation.

Main Methods:

• Utilized the time-dependent configuration interaction single (TDCIS) approach for simulations.
• Employed systematically extendable Li-(Ph)(n)-CN molecules as model systems.

Main Results:

• Demonstrated reduced selectivity of electronic transitions in larger molecules, even with longer laser pulses.
• Identified dynamic molecular polarizations as a key factor diminishing selectivity.
• Showed that few-state models can significantly underestimate these dynamic polarization effects.

Conclusions:

• Dynamic polarizations play a critical role in limiting laser-induced electronic excitation selectivity in larger molecular systems.
• Accurate modeling of molecular systems requires considering more than just a few electronic states to capture polarization effects.