Inelastic Neutron Scattering Study of Phonon Density of States of Iodine Oxides and First-Principles Calculations

[Image: see text] Iodine oxides I(2)O(y) (y = 4, 5, 6) crystallize into atypical structures that fall between molecular- and framework-base types and exhibit high reactivity in an ambient environment, a property highly desired in the so-called “agent defeat materials”. Inelastic neutron scattering experiments were performed to determine the phonon density of states of the newly synthesized I(2)O(5) and I(2)O(6) samples. First-principles calculations were carried out for I(2)O(4), I(2)O(5), and I(2)O(6) to predict their thermodynamic properties and phonon density of states. Comparison of the INS data with the Raman and infrared measurements as well as the first-principles calculations sheds light on their distinctive, anisotropic thermomechanical properties.