[varelse]

They are.

But the previous generation of scientists came of age when Molecular Dynamics was a disappointing tool because of limitations in the Newtonian models and the lack of computational firepower to do sufficient sampling. The latter has been addressed by a combination of Moore's Law and the ongoing migration of molecular dynamics codebases to GPUs, but the former issue remains - a Newtonian approximation to quantum chemistry.

What's surprising is how much one can get out of these simple models despite these limitations, something that was echoed back in 1976 by one of Michael Levitt's papers that led to today's Nobel Prize:

http://csb.stanford.edu/levitt/Levitt_JMB76_Simplified_repre...

[selimthegrim]

There are very deep reasons for this - the Born-Oppenheimer approximation, a central simplifying assumption, imposes some constraints on the system that make it easier to model with (semi)classical dynamics, even when you marry it with modern techniques such as DFT.

Kieron Burke has a nice take on the matter.

http://www.tddft.org/TDDFT2008/talks/KB.pdf

see also http://www-fourier.ujf-grenoble.fr/~joye/simon2006.pdf, esp. its ref. 93