Line broadenings are part of the specification of the spin system. Hence, they are defined via fields in the spin system structure, which contains all information about the spin system and its Hamiltonian.
For all spectral simulations (solid-state cw EPR with pepper, liquid EPR with garlic, ENDOR with salt), line broadenings have to be given.
The line broadenings are given as fields of the spin system structure, which also contains all spin Hamiltonian parameters. Not all broadenings are supported by all simulation funtions. The following table lists the name of the broadening fields and the functions that use them.
lw | lwEndor |
HStrain | gStrain |
AStrain | DStrain |
|
pepper | x | - | x | x | x | x |
salt | - | x | x | - | - | - |
garlic | x | - | - | - | - | - |
chili | - | - | - | - | - | - |
In chili, all parameters relating to line broadenings are given in a separate structure. See the documentation of chili.
All linewidth are understood to be FWHM (full width at half height), independent of the simulation function, the line shape or the detection harmonic. For the conversion to and from peak-to-peak line widths, see the reference page on line shapes.
There are two types of line broadenings
lw
and lwENDOR
).
This can include both Lorentzian and Gaussian broadenings.
lw
|
real, in mT
Isotropic magnetic-field domain line width (FWHM, in mT), used by pepper for convolution of a field-swept spectrum. |
lwEndor
|
real, in MHz
Isotropic frequency-domain line width (FWHM, in MHz) for ENDOR spectra, used by salt for convolution of the stick ENDOR spectrum. |
Inhomgeneous broadenings in solid-state cw EPR spectra are due
to unresolved hyperfine couplings and distributions in Hamiltonian
parameters which are called strains. HStrain
represents the
broadening due to unresolved hyperfine splittings, and gStrain
,
AStrain
and DStrain
represent correlated g-A and correlated
D-E strain, respectively. The total line broadening for a given
orientation is the combination of all individual broadenings.
HStrain
|
1x3 vector of real
, in MHz
Residual line width (full width at half height, FWHM), in Megahertz, describing inhomogeneous broadening due to unresolved hyperfine couplings. The three components are the Gaussian line widths in the x, y and z direction of the g principal axes system. The line width for a given orientation
![]() ![]() ![]() ![]() ![]() HStrain .
|
gStrain
|
1x3 vector of real
Defines the g strain for electron spin 1. It specifies the FWHM widths of the Gaussian distributions of the g principal values (x, y and z). The distributions are completely uncorrelated. If more than one electron spin is specified, the g strain is valid only for the first one. gStrain is correlated
with Astrain .
|
AStrain
|
mx3 vector of real
, in MHz
Vector of FWHM widths (in Megahertz) of the Gaussian distributions of the corresponding principal values in A . The distributions are completely uncorrelated.
AStrain is correlated with gStrain according to the formula above.
|
DStrain
|
2-vector
[FWHM_D FWHM_E] , in MHz
Vector of widths (FWHM) of the Gaussian distributions of the scalar parameters D and E that specify the D matrix of the zero-field interaction. E.g. a DStrain of [10 5] specifies a Gaussian FWHM
of 10 MHz for D and of 5 MHz for E. If the spin system contains more than
one electron spin, DStrain is valid only for the first one.
|
When none of the above inhomogeneous line width parameters applies to your problem, you can always run a loop over any distribution of spin Hamiltonian parameters, simulate the associated spectra and sum them up (including weights of the distribution function) to obtain an inhomogeneously broadened line.