Evaluating Full Width at Half-Maximum (FWHM) from Integrated EPR Spectrum

Finding the full width at half-maximum (FWHM) height of the EPR integrated spectrum/intensity. For such purpose, the EPR spectrum must be available in single integrated form (common absorption-like spectrum). If this is not the case, the derivative EPR spectrum (with the intensity dIepr_over_dB) can be integrated by the eval_integ_EPR_Spec. The FWHM is evaluated as a difference between the points (\(x > x_{\text{max}}\) and \(x < x_{\text{max}}\)) having the intensity closest to the intensity maximum/2 corresponding to one individual EPR line/peak defined by the xlim argument.

Usage

eval_FWHMx_Spec(
  data.spectr.integ,
  x = "B_G",
  Intensity = "single_Integ",
  xlim = NULL
)

Arguments

data.spectr.integ

Data frame object, containing x-column/variable like magnetic flux density, B (in in mT or G) or g-factor/value (unitless) and integrated intensity (common absorption-like spectrum) column/variable.

x

Character string, pointing to name of the x-axis/column/variable (in the original data.spectr.integ) like magnetic flux density B (in mT or G) or g-Value (unitless), default: x = "B_G".

Intensity

Character string, pointing to name of the intensity column/variable (in the original data.spectr.integ) if other than single_Integ (default) name/label is used (such as "Integral_Intensity" or "integral").

xlim

Numeric vector, corresponding to lower and upper limit of the selected x-region, e.g. xlim = c(3495.4,3595.4) (B in G) or xlim = c(2.004,2.001) (g dimensionless). Default: xlim = NULL (corresponding to the entire x-range).

Value

Numeric value of the FWHM, directly from EPR spectrum, depending on the x variable => either in mT/G or unitless in case if g-factor is presented on abscissa.

See also

Other Evaluations: eval_DeltaXpp_Spec(), eval_extremeX_Spec(), eval_gFactor(), eval_gFactor_Spec(), eval_interval_cnfd_tVec(), eval_nu_ENDOR(), eval_peakPick_Spec()

Examples

## simulation of the phenalenyl/perinaphthenyl (PNT) radical
## in integrated form:
pnt.sim.integ.iso <-
  eval_sim_EPR_iso(g = 2.0027,
    instrum.params = c(Bcf = 3500, # central field
                       Bsw = 100, # sweep width
                       Npoints = 4096,
                       mwGHz = 9.8), # MW Freq. in GHz
    B.unit = "G",
    nuclear.system = list(
      list("1H",3,5.09), # 3 x A(1H) = 5.09 MHz
      list("1H",6,17.67) # 6 x A(1H) = 17.67 MHz
     ),
    lineSpecs.form = "integrated",
    lineGL.DeltaB = list(0.54,NULL), # Gauss. FWHM in G
    Intensity.sim = "single_Integ"
  )
#
## FWHM of one of the central
## lines/peaks (`xlim = c(3494,3496.5)`)
## from the simulated spectral data:
eval_FWHMx_Spec(pnt.sim.integ.iso$df,
                x = "Bsim_G",
                Intensity = "single_Integ",
                xlim = c(3494,3496.5)
                )
#> [1] 0.537
#
## interactive plot of the above-simulated
## EPR spectrum in order to check the values:
plot_EPR_Specs2D_interact(pnt.sim.integ.iso$df,
  x = "Bsim_G",
  x.unit = "G",
  Intensity = "single_Integ",
  lineSpecs.form = "integrated"
 )