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B14
,The Baldwin 2014 2-site exact solution relaxation dispersion model for [[SQ CPMG-type data]] for all time scales whereby the simplification {{:R2Azero}} = Intro ={{:R2Bzero}} is assumed. This model is labelled as '''B14''' in [[Relaxation dispersion citation for relax|relax]].
The Baldwin 2014 advantage of this code will be that you'll always get the right answer provided you've got 2-site exact solution relaxation dispersion model for [[SQ CPMGexchange, in-phase magnetisation and on-type data]]. This model is labelled as '''B14''' in [[Relaxation dispersion citation for relax|relax]]resonance pulses.
== Comments from the Author ==During the implementation of model B14, Andrew Baldwin wished to raise the attention to: '''1) Danger of errors of approximations'''.<br>'''2) That optimal accuracy analysis should include off resonance effects'''This model is not implemented yet. Please read:* {{#lst:Citations|MyintIshima09}}* {{#lst:Citations|Bain11}} '''Differential relaxation effects''':<br> Please read:* {{#lst:Citations|Vallurupalli07}}* {{#lst:Citations|Vallurupalli08}}
== Equation ==
<math>
\tau_{\textrm{CP}} = \frac{1}{4\nu_\textrm{CPMG}} \\
\alpha_- = \Delta R_2 + k_{\textrm{AB}} - k_{\textrm{BA}} \\
\zeta = 2 \Delta \omega \, \alpha_- = h_1\\
\Psi = \alpha_-^2 + 4 k_{\textrm{BA}} k_{\textrm{AB}} - \Delta \omega^2 = h_2\\
== Parameters ==
The B14 model has the parameters{{{:R2zero}}, ..., {{:pA}}, {{:Deltaomega}}, {{:kex}}}. == Code ==[http://search.gmane.org/?query=https%3A%2F%2Fgna.org%2Fsupport%2F%3F3154&author=&group=gmane.science.nmr.relax.scm&sort=revdate&DEFAULTOP=and&TOPDOC=10&xP=https%09gna%09org%09support%093154&xFILTERS=Gscience.nmr.relax.scm---A Commits that created the code, approx 20-30 commits, with corrections. ] [https://gna.org/support/?3154 Here is gna.org tracker that followed this code. It includes valuable comments.] The library code: {{relax url|path=lib/dispersion/b14.py}} The target function func_B14(): {{relax url|path=target_functions/relax_disp.py}} === Example graph of test data ===[[File:CPMG Model B14 Example data disp 1 H.png|thumb|center|upright=2|Graph from systemtest "relax -s Relax_disp.test_baldwin_synthetic"]]
== Reference ==
The reference for the B14 model is:
* A.J. Baldwin (2014). An exact solution for R2,eff in CPMG experiments in the case of two site chemical exchange. ''J. Magn. Reson.'', 2014. ([http{{#lst://dx.doi.org/10.1016/j.jmr.2014.02.023 10.1016/j.jmr.2014.02.023]).Citations|Baldwin14}}
== Related models ==
== Links ==
The [[Relaxation dispersion citation for relax|implementation of the CR72 B14 model in relax]] can be seen in the:* [http://www.nmr-relax.com/manual/The_reduced_B14_2_site_CPMG_model.html relax manual],* [http://www.nmr-relax.com/api/3.1/lib.dispersion.b14-module.html API documentation],* [http://www.nmr-relax.com/analyses/relaxation_dispersion.html#B14 relaxation dispersion page of the relax website].
== See also ==
[[Category:Models]][[Category:Dispersion models]][[Category:Relaxation_dispersionanalysis]]