Tuesday 4 November 2008


What you need in computational chemistry is - not so very surprisingly - computers. You can either use your own little cluster. You can try to get time at a super computer. Or you can have other people do the work for you.

Actually I am advertising for the competition a little bit but I think the idea is pretty cool. You are probably used to distributed computing with the SETI project. QMC@home does the same in quantum chemistry. The disadvantage of their Quantum Monte Carlo approach is that you need a huge amount of computer time. The advantage is that you can easily distribute it over many computers with little communication between them. The ideal case for voluntary grid computing. It is organised over the same BOINC platform that is also used by the SETI project. So if you download it and get bored by Quantum Monte Carlo, you can switch the system and start looking for extra terrestrial life.

QMC@home has this screensaver that tells you what's going on. (In principle it should have it, it's not working on my computer).

In this case they are computing interaction energies for the cytosine dimer. Van-der-Waals dispersion interactions are a difficult problem because you need a highly correlated wave function to describe them correctly. Maybe QMC is a good way to do it.

I like the idea because it seems like a waste to have so many unused computers standing around everywhere. It has to be said though, that the computation uses up energy. But then when I look at people that don't even turn off their screens when they leave their computers, it does not seem like they would complain about a little bit of extra energy use.
It would probably be a good idea if they had some kind of reimbursement system. But on the other hand it is kind of fun as it is and you get a sense of accomplishment just for keeping your computer on for some time. And now I also have an excuse for not turning it off every time I leave my workplace.

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