Surface-enhanced infrared absorption (SEIRA) spectroscopy exploits the field enhancement near nanophotonic structures for highly sensitive characterization of (bio)molecules. The vibrational signature observed in SEIRA spectra is typically interpreted as field-enhanced molecular absorption. Here, we study molecular vibrations in the near field of single antennas and show that the vibrational signature can be equally well explained by field-enhanced molecular scattering. Although the infrared scattering cross section of molecules is negligible compared to their absorption cross section, the interference between the molecular-scattered field and the incident field enhances the spectral signature caused by molecular vibrational scattering by 10 orders of magnitude, thus becoming as large as that of field-enhanced molecular absorption. We provide experimental evidence that field-enhanced molecular scattering can be measured, scales in intensity with the fourth power of the local field enhancement and fully explains the vibrational signature in SEIRA spectra in both magnitude and line shape. Our work may open new paths for developing highly sensitive SEIRA sensors that exploit the presented scattering concept., This work was financially supported by: Grant CEX2020-001038-M funded by MICIU/AEI /10.13039/501100011033. Grant PID2020-115221GA-C44 (SNOMCELL) funded by MICIU/AEI /10.13039/501100011033 (M.S.). Grant PID2021-123949GB-I00 (NANOSPEC) funded by MICIU/AEI /10.13039/501100011033 and by ERDF/EU (R.H.)., With funding from the Spanish government through the "Unit of Excellence Maria de Maeztu" accreditation (CEX2020-001038-M)., Peer reviewed

nano-FTIR data is provided as interferogram files ending in "Interferograms.txt.txt" within the individual folders containing the string "NF S". Row: not used Column: not used Run: number of interferogram acquisition Depth: pixel number within one interferogram M: not used O0A: amplitude in V of the 0th demodulation order O0P: phase in radians of the 0th demodulation order O1A: amplitude in V of the 1st demodulation order O1P: phase in radians of the 1st demodulation order O2A: amplitude in V of the 2nd demodulation order O2P: phase in radians of the 2nd demodulation order O3A: amplitude in V of the 3rd demodulation order O3P: phase in radians of the 3rd demodulation order O4A: amplitude in V of the 4th demodulation order O4P: phase in radians of the 4th demodulation order O5A: amplitude in V of the 5th demodulation order O5P: phase in radians of the 5th demodulation order, Additionally, s-SNOM images for finding the antennas prior to nano-FTIR spectroscopy can be found in the folders containing the string "WL", This is the nano-FTIR data set as shown in Figs 3 and 5 of our publication "Experimental verification of field-enhanced molecular vibrational scattering at single infrared antennas" by D. Virmani et al. This data set was acquired with a NeaSNOM microscopy (attocube AG) and can be opened with Gwyddion (https://gwyddion.net/). Please see the files "notes.txt" within the zip file provided for an identification of the individual data sets., Peer reviewed