Theoretical Description of Infrared Near-Field Spectroscopy of In- and Out-of-Plane Molecular Vibrations in Thin Layers.

ABSTRACT: Infrared nanospectroscopy, based on scattering-type scanning near-field optical microscopy (s-SNOM), allows for chemical nanoidentification of organic composite layers by local probing of their molecular vibrations. However, the conditions for probing in-plane and out-of-plane molecular vibrations by this technique remain largely unexplored. Here, we perform a systematic theoretical study of the local infrared near-field response of isotropic and anisotropic thin layers using electrostatic numerical calculations, complemented by analytical electrodynamic point-dipole model calculations. Specifically, we study uniaxial thin layers exhibiting molecular vibrations with different orientations on highly and weakly reflecting substrates. We find that both in-plane and out-of-plane molecular vibr

SUBMITTER: Pascual Robledo I 

PROVIDER: S-EPMC12272971 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature