Spectroscopic characterisation of metastable photoswitches for CO2 capture and release.

The design of functional molecules for seawater CO2 capture via photoisomerisation offers a less energy-intensive approach for atmospheric CO2 depletion, yet requiring efficient photon absorption at wavelengths matching the solar irradiance spectrum. Computational photochemistry can predict absorption spectra, reducing reliance on trial-and-error experiments. However, guiding principles for reliably describing the shape and absolute intensity of absorption spectra are lacking. Herein, we present a simple protocol for calculating absorption spectra of photoacids in solution with quantitative accuracy. This approach enables predictive modelling of photoactive systems and is readily transferable to other solar-driven technologies based on functional molecules.