An intuitive and physical model explaining the metal independent blue color, which is now associated with the solvated electron, was provided by Jortner in 1959. Jortner assumed that the electron is trapped within a cavity of ammonia molecules, treated as a continuous homogeneous medium, characterised by a low and high frequency dielectric constant. Thus, the electron was confined within a well whose potential was constant within a cavity of radius R, and varied smoothly outside of the cavity. Jortner described the blue color as arising from a 1s → 2p electronic transition of this electron, for which an energy of 0.8 eV was calculated assuming R = 3 -3.2 Å, in excellent agreement with the absorption maximum characteristic of the solvated electron. Though intuitive, this model failed to describe the asymmetric long tail of the absorption spectrum (which, in fact, turns out to be the source of the characteristic blue color), the line-shape, and other measured properties, thus necessitating improvements to Jortner's simplest model. 106 An orbital-based picture of electron solvation presents an alternative approach to Jortner's model. The highest occupied molecular orbital (HOMO) of ammonia (Figure )