Solvated electron spectrum in supercooled water and ice

The spectrum of the solvated electron was recorded between 310 and 830 nm in water supercooled down to −18 °C, and in ice-Ih between −5 °C and −34 °C. The absorption maximum in liquid water continues to blue shift by 0.0022 eV/degree from high temperatures down to −18 °C, regardless of water bulk density. We suggest that the increasing free volume of the water below 4 °C due to formation of tetrahedral bonding structures is unavailable to the electron. The spectrum of electrons trapped in a vacancy site in ice-Ih is very similar to the liquid on the blue-side, but much narrower on the red side.