Determine whether high-energy-mode trends converge

Determine whether infrared irradiation of the bending and libration modes of porous amorphous solid water exhibits the same restructuring and desorption trends as OH-stretching irradiation at higher absorbed-photon numbers, or whether libration-mode irradiation produces more efficient restructuring.

Background

The experiments found comparable restructuring behavior for the investigated vibrational modes over the accessible energy ranges, but the FEL could not provide sufficient power at the bending and libration wavelengths to reach the absorbed-photon numbers achieved for OH-stretching irradiation. The authors therefore could not determine whether the apparent mode-dependent behavior persists at higher excitation levels or whether the libration mode becomes more efficient than the OH-stretching mode under comparable photon exposure.

References

In this way, it cannot be tested whether, for higher numbers of absorbed photons, the restructuring and desorption from irradiations at the bending and libration modes show the same trends as the irradiations at the OH-stretching vibration or whether the libration mode may result in more efficient restructuring.

— Infrared photoprocessing of porous amorphous solid water with a free electron laser  (2608.25473 - Schrauwen et al., 26 Aug 2026) in Section 3.3, “Trends in the restructuring and desorption”

Our experiments cannot probe the order of the desorption and restructuring processes, as the shortest irradiation time measuring restructuring lasted for 10~s.

— Infrared photoprocessing of porous amorphous solid water with a free electron laser  (2608.25473 - Schrauwen et al., 26 Aug 2026) in Section 3.3, “Trends in the restructuring and desorption”

For the current study, we cannot exclude similar indirect processes, and if this is the case, the binding energy of the desorbing molecule appears to be the determining factor.

— Infrared photoprocessing of porous amorphous solid water with a free electron laser  (2608.25473 - Schrauwen et al., 26 Aug 2026) in Section 4, “Conclusion and astrophysical Implications”