Difference between revisions of "Slowpass.m"
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{{DISPLAYTITLE:slowpass.m}} __NOTOC__ | {{DISPLAYTITLE:slowpass.m}} __NOTOC__ | ||
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Slow passage detection - calculates spectrum values at the user specified frequency positions using the Fourier transform of the Liouville - von Neumann equation. The biggest advantage over the fid+fft style detection is easy parallelization and the possibility of getting spectrum values at specific frequencies without recalculating the entire free induction decay. | Slow passage detection - calculates spectrum values at the user specified frequency positions using the Fourier transform of the Liouville - von Neumann equation. The biggest advantage over the fid+fft style detection is easy parallelization and the possibility of getting spectrum values at specific frequencies without recalculating the entire free induction decay. | ||
==Syntax== | ==Syntax== | ||
| − | spectrum=slowpass(spin_system,parameters,H,R,K) | + | spectrum=slowpass(spin_system,parameters,H,R,K) |
==Arguments== | ==Arguments== | ||
| − | parameters.sweep vector with two elements giving | + | parameters.sweep vector with two elements giving |
the spectrum frequency extents | the spectrum frequency extents | ||
in Hz | in Hz | ||
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==Outputs== | ==Outputs== | ||
| − | spectrum - the spectrum of the system with the specified | + | spectrum - the spectrum of the system with the specified |
| − | + | starting state detected on the specified coil | |
| − | + | state within the frequency interval requested | |
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==Examples== | ==Examples== | ||
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The 14N overtone MAS spectrum of glycine recorded using this method (examples/nmr_overtone/mas_glycine_1.m) appears below. FID+FFT simulation in this system is much slower. | The 14N overtone MAS spectrum of glycine recorded using this method (examples/nmr_overtone/mas_glycine_1.m) appears below. FID+FFT simulation in this system is much slower. | ||
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==Notes== | ==Notes== | ||
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Relaxation must be present in the system dynamics, or the matrix inversion operation would fail to converge. The relaxation matrix R should *not* be thermalized. | Relaxation must be present in the system dynamics, or the matrix inversion operation would fail to converge. The relaxation matrix R should *not* be thermalized. | ||
==See also== | ==See also== | ||
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[[acquire.m]], [[fieldscan_enlev.m]], [[fieldscan_magn.m]], [[fieldsweep.m]], [[rapidscan.m]] | [[acquire.m]], [[fieldscan_enlev.m]], [[fieldscan_magn.m]], [[fieldsweep.m]], [[rapidscan.m]] | ||
''Version 2.3, authors: [[Ilya Kuprov]]'' | ''Version 2.3, authors: [[Ilya Kuprov]]'' | ||
Revision as of 15:50, 5 April 2026
Slow passage detection - calculates spectrum values at the user specified frequency positions using the Fourier transform of the Liouville - von Neumann equation. The biggest advantage over the fid+fft style detection is easy parallelization and the possibility of getting spectrum values at specific frequencies without recalculating the entire free induction decay.
Syntax
spectrum=slowpass(spin_system,parameters,H,R,K)
Arguments
parameters.sweep vector with two elements giving
the spectrum frequency extents
in Hz
parameters.npoints number of points in the spectrum
parameters.rho0 initial state
parameters.coil detection state
H - Hamiltonian matrix, received from context function
R - relaxation superoperator, received from context function
K - kinetics superoperator, received from context function
Outputs
spectrum - the spectrum of the system with the specified
starting state detected on the specified coil
state within the frequency interval requested
Examples
The 14N overtone MAS spectrum of glycine recorded using this method (examples/nmr_overtone/mas_glycine_1.m) appears below. FID+FFT simulation in this system is much slower.
Notes
Relaxation must be present in the system dynamics, or the matrix inversion operation would fail to converge. The relaxation matrix R should *not* be thermalized.
See also
acquire.m, fieldscan_enlev.m, fieldscan_magn.m, fieldsweep.m, rapidscan.m
Version 2.3, authors: Ilya Kuprov
