# Overtone a.m

Frequency domain overtone acquisition.

## Syntax

spectrum=overtone_a(spin_system,parameters,H,R,K)

## Description

The function performs frequency-domain acquisition at the overtone frequency. Because time-domain overtone spectroscopy is difficult (see http://dx.doi.org/10.1039/C4CP03994G for details), this mode of acquisition is preferable in practice. Simulations assumptions should be set to 'qnmr'.

## Arguments

parameters.sweep - vector with two elements giving the spectrum frequency extents in Hz around the overtone frequency parameters.npoints - number of points in the spectrum parameters.rho0 - initial state parameters.coil - detection state H - Hamiltonian commutation superoperator R - unthermalised relaxation superoperator K - chemical kinetics superoperator

## Returns

The function returns the populations of the detection state at the frequencies specified.

## Examples

The following 15N overtone spectrum is produced by examples/nmr_overtone/mas_glycine_1.m example file:

## Notes

Relaxation must be present in the system dynamics, or the matrix inverse-times-vector operation performed by the frequency domain detection module would fail to converge. The relaxation superoperator should *not* be thermalised.

## See also

overtone_cp.m, overtone_dante.m, overtone_hmqc.m, overtone_pa.m, slowpass.m

*Revision 3284, authors: Ilya Kuprov, Phil Williamson, Marina Carravetta*