Wet electrons

A wet electron in <a href="/facts/Chemistry/SrNqkGVm">chemistry</a> and <a href="/facts/Physics/a7aH2y08">physics</a> is an <a href="/facts/Electron/L0KBo5cW">electron</a> in a medium (such as <a href="/facts/Water/0lkXnJPK">water</a>) that has been excited into a state that is localized but not associated with a particular <a href="/facts/Atom/FoQ4kGN5">atom</a> or <a href="/facts/Molecule/N9ljSfFq">molecule</a>. This kind of state is often said to be “quasi-<a href="/facts/Free_particle/Fjbx90yW">free</a>.” Wet electrons become <a href="/facts/Solvation/JVM6j8R1">solvated</a> by glassy and liquid media similarly to an ion, resulting in a <a href="/facts/Solvated_electron/mLplrtI8">solvated electron</a>. This is possible since the timescale of their existence in water at room temperature (and other <a href="/facts/Hydrogen_bond/85V86IIg">hydrogen bonded</a> liquids) is comparable to or larger than that for rearrangements of the hydrogen bond network, ranging from femtoseconds to picoseconds among media studied.

The hydrogen atoms of water molecules can either participate in the network of <a href="/facts/Hydrogen_bonds/85V86IIg">hydrogen bonds</a> or be “<a href="/facts/Dangling_bond/HmG4tu3x">dangling</a>.” The dangling hydrogen atoms are the ones which (transiently) stabilize the wet electron state. In various liquids and glasses, particularly hydrogen bonding ones, wet electrons develop solvation shells with well-defined geometric structures. Elucidating these structures was an early application of <a href="/facts/Electron_paramagnetic_resonance/TDHV8c9e">ESR</a> spectroscopy.
Advanced experimental techniques such as <a href="/facts/Radiolysis/BzPNnEvu">pulse radiolysis</a> and <a href="/facts/Two-photon_photoelectron_spectroscopy/vX20xf8H">time-resolved spectroscopy</a> have been pivotal in detecting and studying the behavior of wet electrons. These methods allow scientists to generate wet electrons and observe their transient absorption features and monitor their behavior in real-time. Theoretical studies, particularly those using hybrid functional molecular dynamics simulations, provide deeper insights into the dynamics and energetics of wet electrons. These studies have shown that the spatial extent of the wet electron fluctuates rapidly while the surrounding molecules rearrange to solvate the electron.
The term “wet electron” is variably used in the literature to describe: the transition state of an electron between the quasi-free and solvated states; any electron that is not bound to a particular atom or molecule in a noncrystalline medium; a solvated electron; or something in between.

Wet electrons open-in-new

Wet electrons