Supplemental materials for: "Solvation Structure and UV-Visible Absorption Spectra of the Nitrate Anion at the Air-Ice Interface by First Principles Molecular Simulations" Margaret L. Berrens, Zekun Chen, Kam-Tung Chan, Cort Anastasio, and Davide Donadio Contents: 1)AIMD: Each folder in the AIMD folder contains the following for each system sample: * CP2K input: CP2K input files used for First-principles MD simulations. * pdb file for a pre-equilibrated bulk water or ice slab. Equilibration done using classical MD for 100 ns (described in our manuscript). *xyz file for a pre-equilibrated bulk water or ice slab. Equilibration done using classical MD for 100 ns (described in our manuscript). 2)Metadynamics: *CP2K input: CP2K input file for the well-tempered meta dynamics run *Plumed input: Plumed input file to use in conjunction with CP2K for the well-tempered meta dynamics run *Plumed output: (HILLS) Plumed output file that contains the the deposited Gaussians throughout the well-tempered metadynamics simulation generated by PLUMED. 3)TDDFT: *Orca input: Orca input file for TDDFT calculations from a sample frame *Orca output: Sample Orca output files from both an ice surface run and a solution run.