POPC monolayers simulated at a varying area per lipid in the NVT ensemble. The Charmm36 lipid model [1] is employed together with the 4-point OPC water model [2]. Each system contains two monolayers with 64 lipids each, except for the system '120large', which contains 256 lipids per monolayer. These monolayers are separated by a water slab, and surrounded by vacuum. The number in the filename corresponds to the area per lipid in Ångströms. The starting structures were taken from [3], which also provides detailed information on system setup. The simulations in [3] used TIP3P water and Slipids lipids, which were replaced by OPC water and Charmm36 lipids, followed by energy minimization and production runs. All trajectories, 100 ns long, are simulated with Gromacs 5.0.x [4] using the parameters given in the mdp file. The topologies for the lipids can be obtained from Charmm-GUI and for the OPC water model from https://bioinformatics.cs.vt.edu/~izadi/ . Note that .top and .ndx files are for all systems except for the "120large". [1] DOI: 10.1021/jp101759q [2] DOI: 10.1021/jz501780a [3] DOI: 10.1016/j.bbamem.2016.09.015 [4] DOI: 10.1016/j.softx.2015.06.001