In situ Raman spectra of hydrogen in large cages of hydrogen+tetrahydrofuran mixed hydrates

Abstract

Large-cage occupancy of hydrogen (H2) in the H2+tetrahydrofuran (THF) hydrates has been ever reported only in the ex situ spectroscopic measurements with the quenched hydrate sample. In the present study, to verify the proof-of-concept for the large-cage occupancy of H2 competitive with THF, in situ Raman spectra of H2 in the H2+THF mixed hydrates were detected at 74.3MPa and 265K without the quenching procedure. The Raman spectra reveal that H2 molecules occupy a part of large cages of the H2+THF mixed hydrates at a thermodynamically unstable region of simple H2 hydrate.