Finding Bond Lengths

[sol66]

So I'm doing research on a particular protein and I need to find bond lengths to parameterize the chromophore. I currently have a bunch of IR Spectroscopic data and I'm thinking I can use the wavelengths of absorptions between bonds to somehow find bond length. I am actually a physicist and so anything regarding the molecular physics of this would be helpful. Also If I can't calculate bond lengths, I might need to do an "AB Initio QM" calculations of the bonds. Would you have any good sources on how this is done and what software I can use?

[Maxim Zh]

Try this software: http://www.abinit.org/

[sol66]

Thanks a bunch for the software. It seems like it'll solve my problem. Together with the data I have and the software, it should be pretty easy to solve what I'm looking for. It should be more accurate then just taking general bond lengths found in other chemicals.