OMNI-P2x universal neural network potential for excited-state simulations.

Photo-active molecular systems play an essential role in modern science and technology, finding applications in solar cells, organic light-emitting diodes, reaction catalysis, photodynamic therapy, and beyond. The rational design of photo-responsive molecules requires an understanding of the photophysical and photochemical processes underlying their operation, which can be gained via the first-principles quantum-mechanical calculations that are prohibitively expensive for high-throughput investigations. To break through this limitation, here we introduce OMNI-P2x: a universal neural network potential for molecular excited and ground electronic states. OMNI-P2x can be used, directly or after fine-tuning, to perform a wide range of photophysical and photochemical simulations. OMNI-P2x approaches the accuracy of time-dependent density functional theory methods at a fraction of the computational cost, while being more accurate and faster than established semiempirical methods for excited-state simulations. Here, we demonstrate its use in UV/Vis absorption spectroscopy, real-time photodynamical simulations, and in the rational design of visible-light-absorbing azobenzene systems.