Ice: a most curious substance

Ice fishing on the Ottawa River — no Periodic Hartree-Fock Calculations required. (Courtesy: AlainV).

By Hamish Johnston

One of my favourite memories of childhood is travelling across a frozen lake in the backseat of a circa-1975 Buick LeSabre (a very large car) on our way to do a bit of ice fishing.

The ice was over a foot thick, and we were secure in the knowledge that it would hold the LeSabre — and the hundreds of other cars on the lake.

What I didn’t know back then was just how complicated the stuff we were driving on is — and how much grief it has given to physicists brave enough to try to understand it.

For example, Andreas Hermann and Peter Schwerdtfeger of Massey University in New Zealand have just published a paper entitled Ground-State Properties of Crystalline Ice from Periodic Hartree-Fock Calculations and a Coupled-Cluster-Based Many-Body Decomposition of the Correlation Energy .

They say their result “hints at the possibility to accurately simulate ab initio water”. In other words, at some point in the future we may be able to understand why a seemingly simple combination of hydrogen and oxygen has myriad wonderous and life-giving properties.

Indeed, one of the most curious (alleged) properties of water is the Mpemba effect whereby hot water freezes faster than cold water. I’m guessing that it will be a while before this can be explained using Periodic Hartree-Fock Calculations.