One of the study’s most exciting revelations is its explanation for the spontaneous formation of hydroxyl radicals and hydrogen peroxide at the surface of pure water microdroplets.
By Pesach Benson, TPS
An Israel-Swedish study released on Tuesday is changing science’s understanding of a basic chemical reaction in water, which has significant implications for pollution control strategies, developing better water treatment technologies, and even impacting studies of interstellar chemistry.
Led by Professor Daniel Strasser from the Hebrew University’s Institute of Chemistry, the research challenges long-standing assumptions about how acid-base reactions occur.
“The electron-transfer mechanisms we’ve uncovered suggest several pathways for spontaneous OH formation at low temperature conditions, without a catalyst or an external energy source,” said Strasser.
“Our work offers new insights not only into the quantum mechanism of electron-transfer dynamics in acid-base chemistry but also into broader processes like atmospheric chemistry, where OH radicals play an essential role.”
The study, in collaboration with Dr. Richard Thomas and Professor Henning Schmidt from Stockholm University, was recently published in the peer-reviewed Nature Chemistry journal.
The research was carried out at Stockholm’s DESIREE (Double ElectroStatic Ion Ring ExpEriment) facility using advanced imaging techniques to track chemical reactions in unprecedented detail.
By analyzing individual reactions, the team discovered two distinct pathways through which the reaction leads to the formation of hydroxyl radicals, molecules that are crucial in many scientific processes.
“This study builds on our previous findings published in Science, where we first identified both electron-transfer and proton-transfer products,” said Thomas.
“Now, we’ve been able to observe the distance at which an electron jumps from OH⁻ to H₃O⁺ and see how this affects the outcome of the reaction. Shorter jumps lead to the production of water and a hydrogen atom, while longer jumps create two hydroxyl radicals and hydrogen gas.”
The study’s findings challenge the traditional view that acid-base reactions occur primarily through proton transfer, showing instead that electron transfer is the main driver in isolated conditions.
“Electron transfer is the primary mechanism in these cases, fundamentally reshaping our understanding of acid-base chemistry,” Strasser explained.
Hydroxyl radicals are key players in atmospheric processes, affecting air quality, climate, and even human health.
One of the study’s most exciting revelations is its explanation for the spontaneous formation of hydroxyl radicals and hydrogen peroxide at the surface of pure water microdroplets.
This phenomenon, which had baffled scientists, now has a clear chemical explanation.
“It is exciting to experimentally visualize the mechanisms that help explain the recently reported spontaneous formation of OH radicals (and subsequently hydrogen peroxide) on the surface of pure water microdroplets—an observation that may fundamentally change how we think about atmospheric chemistry,” Thomas said.
The research also sheds light on a type of chemical reaction known as non-adiabatic reactions, where electrons jump rapidly between different energy states.
hese reactions are essential in many fields but have been difficult to observe and model.
“Providing detailed experimental evidence will enhance our ability to validate and fine-tune theoretical models,” Schmidt said.
The study’s findings have broad implications.
Understanding how hydroxyl radicals form could improve air quality and climate modeling, and could also contribute to medical research related to aging, cancer, and immune response.
The discovery also has potential applications in space science, helping scientists understand chemical reactions in extreme environments like interstellar space.
“These findings open new avenues for research into reaction dynamics in extreme environments, such as interstellar space and planetary atmospheres,” Strasser said.
“They also influence future studies on pollution control, environmental science, and medical applications related to oxidative stress.”