Thermal expansivity of Γ-irradiated clathrate hydrate with intracavity conformational change

The lattice expansion and thermal behavior of γ-irradiated unstable clathrate hydrates are explored to understand the complex physicochemical properties of clathrate hydrates. A previous study revealed that enclathrated methyl vinyl ketone molecules show a peculiar conformational change via a ketyl radical anion after γ-irradiation with an annealing process. We measured the lattice parameters of γ-irradiated binary methyl vinyl ketone + CH₄, O₂, and N₂ hydrates at various temperatures. We observed that induced radical affects the lattice expansion behavior, and the thermal expansion coefficients of γ-irradiated hydrates highly depend on the types of secondary gaseous guest molecules.