Squeezed Protons and Infrared Plasmonic Resonance Energy Transfer

Area of Science:

• * Quantum chemistry
• * Materials science
• * Nanotechnology

Background:

• * Noble metal nanostructures can exhibit unusual nuclear quantum effects.
• * These effects include squeezed vibrational states and plasmonic resonance energy transfer.
• * Studying these phenomena requires advanced theoretical methods.

Purpose of the Study:

• * To investigate nuclear quantum effects near heavy metal nanostructures.
• * To utilize nuclear-electronic orbital density functional theory (NEO-DFT) for this study.
• * To explore proton squeezing and plasmonic energy transfer phenomena.

Main Methods:

• * Employed nuclear-electronic orbital density functional theory (NEO-DFT) with an effective core potential.
• * Modeled a quantum proton between two gold tips (Au₆ clusters).
• * Utilized real-time NEO time-dependent density functional theory (RT-NEO-TDDFT) for a hydrogen fluoride (HF) molecule near an Au nanowire.

Main Results:

• * NEO-DFT calculations showed that quantum proton density can be squeezed as tip distance decreases.
• * RT-NEO-TDDFT demonstrated resonant energy transfer from infrared plasmonic motion in an Au nanowire to the HF proton vibrational stretch mode.
• * The study identified specific instances of nuclear quantum effects near gold nanostructures.

Conclusions:

• * The NEO approach is advantageous for probing nuclear quantum effects.
• * Squeezed proton vibrational states were observed in a quantum proton-gold tip model.
• * Infrared plasmonic resonance energy transfer was demonstrated between an Au nanowire and an HF molecule.