Nanoscale-resolved chemical identification of thin organic films using infrared near-field spectroscopy and standard Fourier transform infrared references

Abstract

We establish a solid basis for the interpretation of infrared near-field spectra of thin organic films on highly reflective substrates and provide guidelines for their straightforward comparison to standard far-field Fourier transform infrared (FTIR) spectra. Particularly, we study the spectral behavior of near-field absorption and near-field phase, both quantities signifying the presence of a molecular resonance. We demonstrate that the near-field phase spectra only weakly depend on the film thickness and can be used for an approximate comparison with grazing incidence FTIR (GI-FTIR) spectra. In contrast, the near-field absorption spectra can be compared more precisely with far-field spectra: for ultrathin films they match well GI-FTIR spectra, while for thick films a good agreement with standard transmission FTIR spectra is found. Our results are based on experimental data obtained by nanoscale FTIR (nano-FTIR) spectroscopy and supported by a comprehensive theoretical analysis. V

Infrared Imaging and Spectroscopy Beyond the Diffraction Limit

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Ultrastructural and SINS analysis of the cell wall integrity response ofAspergillus nidulansto the absence of galactofuranose

“…All spectral data had a zero-fill factor of 4, so that the final spectra were saved at a nominal spectral resolution of 2.1 cm -1 . Please do not adjust margins Please do not adjust margins spatial resolution from the complex-valued second order scattering coefficient, (σ 2 ), [26][27][28] given by equation 1:…”

Infrared Nanospectroscopy Reveals the Chemical Nature of Pit Membranes in Water-Conducting Cells of the Plant Xylem

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