US scientists capture world-first image of atomic oxygen in water

US scientists have achieved a world-first by capturing direct images of individual atomic oxygen dissolved in water, using an advanced laser technique called femtosecond two-photon absorption laser-induced fluorescence (fs-TALIF). Atomic oxygen is highly reactive and important in fields like medicine and industrial chemistry, but its behavior in liquids was previously difficult to study due to its reactivity and the inability of earlier methods to detect it without altering the environment. The fs-TALIF method overcomes these challenges by using ultrafast laser pulses to excite oxygen atoms before water molecules can quench their fluorescence, enabling precise measurement of atomic oxygen concentrations near the water surface. The researchers found that atomic oxygen in water is surprisingly stable, persisting for tens of microseconds and traveling hundreds of micrometers, contrary to prior models that predicted almost immediate reaction upon contact with liquid. This discovery suggests that the chemistry of atomic oxygen in aqueous environments is more complex than previously understood, with significant implications for technologies relying on oxidative reactions in liquids.