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ENDOR/Larmor Frequency of Specific Nucleus

Source: R/eval_nu_ENDOR.R
eval_nu_ENDOR.Rd

Larmor/ENDOR frequency calculations for the analysis in EPR/Electron-Nuclear Double Resonance (ENDOR). Function is inspired by the similar Larmor Frequency Calculator, available online.

Usage

eval_nu_ENDOR(nucle_us_i, B.unit = "G", B.val)

Arguments

nucle_us_i

(Vector) character string in the form like "14N" or c("1H","13C"), pointing to specific nucleus/nuclei, for which the frequency should by calculated. The nuclear g-factors for those nuclei are taken from the isotopes_ds.

B.unit

Character string, denoting the magnetic flux density B unit. Default: B.unit = "G".

B.val

Numeric, magnetic flux density \(B\)-value. This actually corresponds to \(B\) at which the EPR signal saturates to record the ENDOR spectrum/spectra.

Value

Numeric value or vector of nuclear Larmor/ENDOR frequencies in MHz for selected nuclei at \(B\) = B.val.

Details

The frequency in MHz is calculated according to relation $$\nu_{\text{ENDOR}}^{} = - (1/h)\,\mu_{\text{N}}^{}\,g_{\text{n}}^{}\,B\,10^{-6}$$ where \(h\) is the Planck's constant, \(\mu_{\text{N}}^{}\) is the nuclear magneton available from constants package (constants::syms$mun), \(g_{\text{n}}^{}\) is the nuclear \(g\)-factor of the specific nucleus (reported in the package isotopes_ds data frame as g_Nuclear) and finally, the \(B\) denotes the magnetic flux density at which the ENDOR spectra are recorded (see also B.val in arguments). The \(10^{-6}\) coefficient is referred to the resulting frequency in MHz. The negative sign "\(-\)" mirrors the convention to describe the direction of magnetic spin moments precession either counter-clockwise (\(+\), if \(\gamma_{\text{n}}^{} < 0\)) or clockwise (\(-\), if \(\gamma_{\text{n}}^{} > 0\), Levitt MH (2013)).

References

Levitt MH (2013). Spin Dynamics: Basics of Nuclear Magnetic Resonance. Wiley, ISBN 978-1-118-68184-8, https://books.google.cz/books?id=bysFAa4MPQcC.

See also

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

Examples

## Larmor/ENDOR frequency for one selected nucleus
## only, e.g. "14N" at 3486 G
eval_nu_ENDOR(nucle_us_i = "14N",
              B.val = 3486)
#> [1] -1.0728883
#
## Larmor/ENDOR frequency for selected nuclei
## e.g. "1H" and "31P" at saturation
## field of B = 349.9 mT
eval_nu_ENDOR(nucle_us_i = c("1H","31P"),
              B.unit = "mT",
              B.val = 349.9)
#> [1] -14.8978597  -6.0362834