HYSCORE powder spectrum outline.
nucfrq2d(Sys,B0) nucfrq2d(Sys,B0,tauvec)
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.
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)