Mixed atomistic-implicit quantum/classical approach to molecular nanoplasmonics

Area of Science:

• Computational Chemistry
• Materials Science
• Nanotechnology

Background:

• Modeling optical properties of molecular-metal nanostructures is crucial for nanotechnology.
• Existing methods often struggle with the complexity of these systems.

Purpose of the Study:

• To develop and validate a multiscale quantum mechanical (QM)/classical approach for simulating optical properties of molecular-metal nanostructures.
• To extend this model for calculating surface-enhanced Raman scattering (SERS).

Main Methods:

• A combined atomistic-continuum model integrating the boundary element method (BEM) for the nanoparticle core and a fluctuating charge and dipole (ωFQFμ) approach for the surface.
• Numerical comparison with fully atomistic methods to assess accuracy.
• Extension to time-dependent density functional theory (TD-DFT) for SERS calculations.

Main Results:

• The QM/ωFQFμ-BEM model accurately reproduces optical properties of complex nanostructures.
• The continuum/core partition's quality was evaluated and found to be reliable.
• The method was successfully extended to compute SERS spectra.

Conclusions:

• The presented multiscale QM/classical approach provides an efficient and accurate method for studying optical properties of molecular-metal nanostructures.
• This model is a valuable tool for advancing research in plasmonics and SERS.
• The integration of QM/ωFQFμ-BEM offers a robust framework for future nanoscale simulations.