Alkali hydroxide (LiOH, NaOH, KOH) in water: Structural and vibrational properties, including neutron scattering results

Structural and vibrational properties of aqueous solutions of alkali hydroxides (LiOH, NaOH, and KOH) are computed using quantum molecular dynamics simulations for a range of solute concentration between 1 and 10 M. Element-resolved partial radial distribution functions, neutron and X-ray structure factors, and angular distribution functions are computed for the three hydroxide solutions as a function of concentration, as well as vibrational spectra. Our results are validated with the available neutron data for 17 M concentration of NaOH in water¹. We found that the larger ionic radius () and higher concentration disturb the hydrogen-bond network of water, resulting in more disordered cationic hydration shell. These ab initio simulation data can be used to guide future elastic and inelastic neutron-scattering experiments.