Two Forms of Water on the Moon
Water ice appears to be present in some permanently shaded craters on the moon. In addition we can say with great certitude there is also "primordial water" on the moon: remnants of what is left behind by the traces of H2O that were dissolved in the rocks ejected from the Earth 4+GYrs ago during the moon-forming impact.
To learn about these traces of dissolved H2O we look at terrestrial igneous rocks. They contain peroxy defects, introduced by O3Si-OH HO-SiO3 pairs undergoing a redox conversion to O3Si-OO-SiO3 + H2. With respect to the moon we need to consider the possibility that the H2 molecules may have diffused out of lunar rocks. In this case we arrive at very interesting conclusion: though lunar rocks may once have contained solute H2O, they now only contain peroxy defects – little or no H or O3Si-OH. Therefore, in order to look for primordial lunar H2O, one would have to look not for H but for peroxy defects.
Application of stress/heat/UV) causes the peroxy bond to break. An electron from a nearby O2– then jumps into the broken peroxy bond. The O2–, which donated the electron, thereby turns into O–, i.e. a defect electron in the oxygen anion sublattice, a positive hole h•, a highly mobile charge carrier capable of propagating out of the stressed/heated/UV-irradiated rock, traveling fast and far.
When positive holes recombine, ~2.2 eV are released, causing the new peroxy bond too be born in an excited state, equivalent to a vibrational temperature of ~25,000 K. To dissipate this energy: (i) infrared photons are emitted corresponding to the downward transitions between the vibrational quantum states of the OO oscillator or (ii) disproportionation occurs, i.e. one of the O– robs the other O– of its electron, turning into O2–, while the O–, which has lost its electron, turns into an O atom, that leaves the surface in an O(1D) excited state emitting VIS light at 630 nm (~2.0 eV).
It is as yet unknown whether lunar rocks contain peroxy defects. However, it should be possible to find out. Peroxy defects will break up releasing positive holes upon impacts and when/or UV light hits the moon surface at the morning terminator. The h• charges will spread outward. Recombination should lead to spectroscopically distinct IR photon emission and possibly to excited O atoms causing a red glow at 630 nm.
For landed missions to moon, one could measure the electric potential associated with the activation of the h• charge carriers and possibly chemical effects due to the highly oxidizing nature of the O-.