DATA REPOSITORY - SURFACE-ENHANCED RAMAN SCATTERING AND SURFACE-ENHANCED INFRARED ABSORPTION BY PLASMON POLARITONS IN THREE-DIMENSIONAL NANOPARTICLE SUPERCRYSTALS This data repository contains experimental Raman and infrared spectra, optical spectra, as well as simulated data of layered gold nanoparticle supercrystals. The data are subdivided into three folders for 1. Experimental surface-enhanced Raman scattering (SERS) spectra and reference measurements 2. Experimental surface-enhanced infrared absorption (SEIRAS) spectra and reference measurements 3. Spectra and electric field enhancement from finite-difference time-domain (FDTD) simulations Each folder contains a readme file that describes the data format and how the data were obtained.