A Study of the Raman Spectrum of Simple Clathrate Hydrates of Hydrogen

Zaghloul, M. A. S., N. M. Salem, and S. M. E. - Sheikh, A Study of the Raman Spectrum of Simple Clathrate Hydrates of Hydrogen, , Egypt, Cairo University, 2013.

Thesis Type:

M.Sc Thesis


Clathrate hydrates are molecular structures in which water molecules form
molecular cages that host other species of molecules. These structures are formed
as a result of phase transition under specific temperatures and pressures. The shape
and stability of the structure is dependent on the guest molecules. Clathrate
hydrates are immensely present in nature, and are expected to appear in various
applications like in transport, and storage of other molecules. They are also
thought of as the future worldwide energy reservoir. Raman spectroscopy offers an
effective way to understand the dynamics of such crucial structures. Raman
spectroscopic measurements were obtained from samples of simple clathrate
hydrates of hydrogen and hydrogen deuteride, using a novel cell that allowed us to
witness the formation of clathrates, and perform in situ measurements upon them.
Understanding the Raman spectrum will help unravel new and interesting traits of
enclathrated molecules, as it reveals their quantum dynamics inside molecular
cages. The cluttered region of the Raman spectrum assigned to the vibrational
states with different occupancies have been analyzed, and a new interpretation of
this region of the spectrum is proposed in this work, based on calculations of
average occupancy per large cage for samples formed at different synthesis
pressures, and subjected to heating and quenching cycles.

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