IIT-M researchers stumble upon future source of fuel

They have formed such hydrates in the vacuum, one thousand billion times below the atmospheric pressure called Ultra-High Vacuum (UHV) and temperature close to minus 263 degree Celsius (10 Kelvin) which are the conditions present in deep space.

“Normally, in UHV experiments, spectroscopic changes are monitored only for minutes, may be an hour. I thought that why not wait for days and kept observing the changes. After all, ice and methane have been sitting in the space for millions of years,” said Professor Pradeep, a senior author of the study.

Clathrate hydrates are molecules like methane and carbon dioxide trapped in well-defined cages of water molecules forming crystalline solids. They are formed at high pressures and low temperatures at places such as the ocean floor, hundreds of metres below the sea level. This discovery of hydrates is highly unexpected at extremely low pressures and ultra-cold temperatures and may have several implications for the chemistry of such atmospheres.

An experimental UHV was specially built for such studies, which housed several spectroscopic probes. Nanometre thin layers of ice and methane were prepared by condensing a mixture of the gases on a specially made single crystal of ruthenium metal. The ruthenium metal surface was cooled to low temperatures initially.

The formation of hydrates was studied by spectroscopy. At first, when the gases were deposited, the spectroscopic features resembled solids of methane and water ice. However, as the hydrate cage formed with methane trapped in it, the molecule became ‘free’ as in the gas phase.

The observed changes were compared with theoretical simulations which confirmed the hydrate formation. The results were verified with the hydrate formed by standard methods.

Cages of water are not expected to form under such conditions as the water molecules are frozen and cannot move at very low temperatures. Therefore, when they did the experiments initially, nothing surprisingwas seen.