Carbon and van der Waals materials

Red shift of the Me–Frelich resonance and electron pinning at the boundary of a spherical copper nanoparticle surrounded by protons

I. E. Istomin, S. G. Yastrebov, T. N. Vasilevskaya

Ioffe Institute, St. Petersburg

Abstract: This work proposes a model explaining the attachment of C–H bond protons to the surface of copper nanoparticles within an amorphous carbon nanocomposite modified with copper nanoclusters (a-C:H:$\langle$Cu$\rangle$). We demonstrate that the non-covalent interaction between the dipole moment of the C–H bond and induced charges in the copper nanoparticles leads to electron localization near the nanoparticle surface (termed as electron pinning). This phenomenon is accompanied by frequency shifts in the infrared absorption bands of the C–H bonds and a decrease in the electron density within the copper nanoparticles. Consequently, the nanoparticle's plasma frequency decreases, resulting in a redshift of the Mie–Fröhlich resonance into the infrared region of the spectrum.

Keywords: amorphous carbon, non-covalent interactions, Mie–Fröhlich resonance, plasmonics.

Received: 16.05.2025
Revised: 01.06.2025
Accepted: 02.06.2025

DOI: 10.61011/FTT.2025.06.60952.132-25

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