Load a 2D dnpdata object and calculate enhancements

This example demonstrates how to import DNP-NMR data in form of a 2D dnpdata object from an hdf5 file, calculate the DNP enhancement factors and plot the enhancement vs. the applied microwave power. This example uses the 2D data object that was created in a previous tutorial (Create a 2D dnpdata object from set of individual spectra). The sample is 10 mM TEMPO in Toluene measured at 14.5MHz (X-Band ODNP spectroscopy).

Load NMR Spectra

In this example, we will calculate the DNP enhancement factor for each individual DNP spectrum and create a figure showing the DNP enhancement versus the applied microwave power. For this, we will import the 2D dnpdata object created in the previous sample. If you are not yet familiar with how to concatenate individual spectra into the 2D dnpdata object, check out this tutorial: Create a 2D dnpdata object from set of individual spectra.

First, load the 2D dnplab data object:

import dnplab as dnp
from dnplab.processing.integration import integrate

sampleTag = "10 mM TEMPO in Toluene"
file_name_path = "../../data/h5/PowerBuildUp.h5"
data = dnp.load(file_name_path)

Calculate DNP Enhancement Factors

DNPLab provides a convenient way to calculate the DNP enhancement factors by using the calculate_enhancement function. Enhancement factors are calculated using integrals. Integrals can be calculated over the entire spectrum, multiple regions, or can be just a single point. However, without calculating integrals first, the calculate_enhancement function will return an error.

integrals = dnp.integrate(data)
enhancements = dnp.calculate_enhancement(integrals)

In this case, the integral is calculated over the entire spectrum followed by calculating the enhancement factors.

Note

The default behavior of the calculate_enhancement function is to use the first spectrum as the Off signal. If this is the case, the argument off_spectrum is not necessary. If you want to specify a particular spectrum that contains the off signal, use the off_spectrum argument.

# #     The ``calculate_enhancement``` function can also calculate the enhancement for specific regions of the spectrum. THis behavior will be discussed in the next example (:ref:`07_align_nmr_spectra`).

Plot Enhancement Data

Finally, we can plot the enhancement data versus the microwave power.

dnp.fancy_plot(enhancements, title=sampleTag + ", ODNP Enhancements")
dnp.plt.show()