nucfrq2d
Introduced in 1.3
Synopsis

HYSCORE powder spectrum outline.

nucfrq2d(Sys,B0)
nucfrq2d(Sys,B0,tauvec)
Description

nucfrq2d computes and plots the outline of a HYSCORE powder spectrum. Peaks positions are accurate, but all peak intensities are set to 1. The plot thus only shows correlation patterns.

Sys is the spin system structure defining the spin Hamiltonian. In Sys, the electron spin must be 1/2.

B0 gives the magnitude of the external magnetic field in mT.

tauvec is a vector of tau values in nanoseconds. It is used to plot blind spot regions, where the ESEEM signal is suppressed.

The plot shows two octants as is standard for HYSCORE spectra and displays all nuclear frequency correlations in colour. Peaks that correlate frequencies from the α electron manifold on the abscissa with β frequencies on the ordinate are in green, the β-α correlations are in red.

If tauvec is given, a gray-shaded background indicating peak suppression regions (blind spots) is shown. White indicates no suppression, the darker the gray the stronger the suppression.

Examples

Correlation plots can be quite aesthetic. For a fantasy system

Sys = struct('S',.5,'g',[2 2 2],'Nucs','14N',...
  'A',2+[-1 -1 2]*2,'Q',[-1.2 -0.8 2]*1.2);
nucfrq2d(Sys,350);

To observe the peaks due to weakly coupled hydrogens, one best uses two tau values related to the Larmor frequency of hydrogen

Sys = struct('S',1/2,'g',[2 2 2],'Nucs','1H','A',[-1 -1 2]*4+2);
B0 = 350; % in mT
Larmor = larmorfrq(Sys.Nucs,B0)/1e3; % in GHz
tauvec = [1 0.5]./Larmor; % in ns
nucfrq2d(Sys,B0,tauvec)
See also

evolve, salt