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Hi Adrienne-- It turns out that my explaination of the force constants isn't quite right. Marius provides the correct description: > Actually, the force constants are based on the measurement error, and in the > case of the example adrienne loh > was asking about, the dipolar couplings are all normalized relative to NH > (which makes it easier to estimate > the appropriate force constants). > > e.g. let us say the measurement error for the NH dipolar couplings is 1 Hz, > then the final force constant should be around 1. > Let us say that the error for the NC' coupling is around 0.5 Hz. The NC' > couplings are 8.33 times smaller than the NH ones > (from the bond lengths and gyromagnetic ratios), so when normalize to the NH > couplings (by multiplying their values by 8.33) the error would be around 4 > Hz. Since we minimize the square of the difference between observed and > calculated, this would translate into a force constant that should be 1/16 > that use for the NH couplings. to recap: the dipolar coupling data have been prescaled to the NH value using the formula in rdcPotTools.py, and the force constants are the square of the ratio of errors relative to those of HNH. Sorry for the misinformation-- Charles - - -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) Comment: Processed by Mailcrypt 3.5.8 <http://mailcrypt.sourceforge.net/> iD8DBQE/FB0ZPK2zrJwS/lYRAp1jAJ93KRdjIGGA9DwdhsRTYR+toVexRgCfUwG1 KZEk1gPQkO+xMBgaRe0rQx0= =mrT1 - - -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) Comment: Processed by Mailcrypt 3.5.8 <http://mailcrypt.sourceforge.net/> iD8DBQE/FB2vPK2zrJwS/lYRAkDOAJ4pZp+jd8Ko4E9NyMXLaGYYQJznzwCfQqCi gTMOvmR1Y15KLZI76mK1Ek8= =mBXp -----END PGP SIGNATURE-----
