Gang Chen
Carl Richard Soderberg Professor of Power Engineering
Massachusetts Institute of Technology

Recent experiments have revealed that evaporation from hydrogel and porous materials under sunlight can surpass thermal limits, a phenomenon termed super-thermal evaporation. We propose the photomolecular effect, where photons cleave water clusters at the liquid-vapor interface, similar to the photoelectric effect. Experiments on hydrogel show increased evaporation rates under visible light, peaking at 520 nm, cooling the vapor phase, and inducing spectral shifts. We demonstrate this effect at a water-air interface using diverse methods. The interaction is prominent with TM-polarized laser and green light, impacting weather, climate, and water cycles. This phenomenon likely occurs widely in nature, offering new energy and water applications.