Visible light, ultraviolet and x-ray radiation have been found to increase chemical reactivity of water. The irradiated solution of water in acetonitrile reacts with triethyl phosphite considerably faster than the non-irradiated control solution. This phenomenon is accounted for by the decomposition of water clusters under the influence of light with the formation of chemically more active free water molecules.
@article{arxiv.1706.02148,
title = {Influence of light on chemical reactivity of water},
author = {Igor V. Shevchenko},
journal= {arXiv preprint arXiv:1706.02148},
year = {2019}
}