Resampled Opacity Databases for PICASO from the Photochem model

This archive contains resampled opacity databases for the PICASO radiative transfer code. These opacities were computed using the HELIOS-K opacity calculator intended primarily for climate simulations with the Photochem model, but they can also be used to compute planetary spectra of rocky planets that are relatively cool (T < 2000 K). Most of the opacities are HITEMP, while some are HITRAN. For details, and to reproduce these opacities, check out the repository https://github.com/Nicholaswogan/HELIOS-K/ at commit 9ecf36823fab304313c79300c2ca1712876c93e7. See the README.md in that repository for instructions, and look at the file "wogan_data/preprocess.py" for the settings/origin for each opacity. There are two opacity databases. "opacities_photochem_0.1_250.0_R15000.db.zip" extends between 0.1 and 250 microns at R = 15,000. This does not mean that these opacities are suitable for data at R = 15,000! Instead, the resampled opacities has to be down-binned to at least a ~100 times lower resolution. So, this file at R = 15,000 is appropriate for resolutions up to R ~ 150. The file "opacities_photochem_0.1_5.5_R60000.db.zip" exends from 0.1 to 5.5 microns at R = 60,000 K. It is appropriate for resolutions up to R ~ 3000.These opacity databases will only work with PICASO v4.0 and newer. At the time of publishing this archive, v4.0 is not released, and can only be accessed via the `dev` branch on the PICASO GitHub repository. Version 2 This is version 2 of the archive, and makes two small updates. First, the first version O3 was not on the exact same P-T grid as the rest of the species. This caused an error to occur in PICASO (for T > 1000 K), which expects all opacities to be on the same P-T grid. Version 2 fixes this problem. Second, version 1 of the opacity database simply added photolysis cross sections to the cross sections derived from HITRAN/HITEMP line lists. The problem with this approach is that it might double count some opacity. In version 2, we only include the photolysis cross section when the line-by-line cross sections is near zero at that wavelength. Version two files have "_v2" in their filenames.