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Influence of 14N on 13C NMR MAS spectra of glycine¶
The alpha-carbon resonance of glycine, 13C (I=1/2), attached to 14N (I=1). The 14N quadrupolar tensor parameters were obtained from Hexem et al. [1]
import matplotlib.pyplot as plt
import numpy as np
from mrsimulator import Simulator, SpinSystem, Site, Coupling
from mrsimulator.method.lib import BlochDecaySpectrum
from mrsimulator import signal_processor as sp
from mrsimulator.spin_system.tensors import SymmetricTensor
from mrsimulator.method import SpectralDimension
Create a 13C-14N coupled spin system.
spin_system = SpinSystem(
sites=[
Site(isotope="13C", isotropic_chemical_shift=0.0),
Site(
isotope="14N",
isotropic_chemical_shift=0, # in ppm
quadrupolar=SymmetricTensor(
Cq=1.18e6, # in Hz
eta=0.54,
alpha=0,
beta=5 * np.pi / 180,
gamma=0,
),
),
],
couplings=[Coupling(site_index=[0, 1], dipolar=SymmetricTensor(D=-660.2))],
)
Create a BlochDecaySpectrum method.
method = BlochDecaySpectrum(
channels=["13C"],
magnetic_flux_density=3.5338, # in T
rotor_frequency=12000, # in Hz
spectral_dimensions=[SpectralDimension(count=2048, spectral_width=200)],
)
Create the Simulator object and add the method and the spin system object.
Add post-simulation signal processing.
processor = sp.SignalProcessor(
operations=[
sp.IFFT(),
sp.apodization.Gaussian(FWHM="1 Hz"),
sp.FFT(),
]
)
processed_dataset = processor.apply_operations(dataset=sim.methods[0].simulation)
processed_dataset.dimensions[0].to("Hz")
plt.figure(figsize=(4.25, 3.0))
ax = plt.subplot(projection="csdm")
ax.plot(processed_dataset.real, color="black", linewidth=1)
ax.invert_xaxis()
plt.tight_layout()
plt.show()
Total running time of the script: (0 minutes 0.321 seconds)