Subsections


relax_disp.plot_disp_curves

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Synopsis

Create 2D Grace plots of the dispersion curves for each spin system.

Defaults

relax_disp.plot_disp_curves(dir=`grace', y_axis=`r2_eff', x_axis=`disp', num_points=1000, extend_hz=500.0, extend_ppm=500.0, interpolate=`disp', force=False)

Keyword arguments

dir: The directory name to place all of the spin system files into.

y_axis: Option can be either `r2_eff' which plot `r2eff' for CPMG experiments or `r1rho' for R1rho experiments or option can be `r2_r1rho', which for R1rho experiments plot R2.

x_axis: Option can be either `disp' which plot `CPMG frequency (Hz)' for CPMG experiments or `Spin-lock field strength (Hz)' for R1rho experiments or option can be either `w_eff' or `theta' for R1rho experiments, which plot `Effective field in rotating frame (rad/s)' or `Rotating frame tilt angle θ (rad)'

num_points: The total number of points to generate the interpolated dispersion curves with. This value has no effect for the numeric CPMG-based models.

extend_hz: How far to extend the interpolated dispersion curves beyond the last dispersion point, i.e. the nu_CPMG frequency or spin-lock field strength value, in Hertz.

extend_ppm: How far to extend the interpolated dispersion curves beyond the last dispersion point, i.e. the spin-lock offset value, in ppm.

interpolate: Either by option `disp' which interpolate CPMG frequency or spin-lock field strength, or by option `offset' which interpole over spin-lock offset.

force: A flag which, if set to True, will cause the files to be overwritten.

Description

This is used to create 2D Grace plots of the dispersion curves of the nu_CPMG frequencies or spin-lock field strength verses the R2eff/R1rho values. One file will be created per spin system with the name `disp_x.agr', where x is related to the spin ID string. For each file, one Grace graph will be produced for each experiment.

Four sets of curves of R2eff/R1rho values will be produced per experiment and per magnetic field strength. These are the experimental values, the fitted values, the interpolated dispersion curves for the fitted solution, and the residuals. Different dispersion models result in different interpolated dispersion curves. For the numeric models which use CPMG-type data, the maximum interpolation resolution is constrained by the frequency of a single CPMG block for the entire relaxation period. For all other models, the interpolation resolution is not constrained and can be as fine as desired by setting the total number of interpolation points. Interpolated curves are not produced for the `R2eff' model as they are not necessary.

For R1rho models, graphs can be interpolated against Spin-lock offset, but this feature is not available for CPMG experiment types. It is also possible to select values on X-axis of `Effective field in rotating frame w_eff (rad/s)' or `Rotating frame tilt angle θ (rad)'.

For R1rho models, special Y-value R2 R1rho can for example be plotted as function of w_eff. R2 is calculated as: R2=(R1rho - R1 cosˆ2(θ)) / sinˆ2(θ).


The relax user manual (PDF), created 2016-10-28.