Changes

See Figure 1 and 10 in the reference.:  Palmer, A.G. & Massi, F. (2006). Characterization of the dynamics of biomacromolecules using rotating-frame spin relaxation NMR spectroscopy. Chem. Rev. 106, 1700-1719 [http* {{#lst://dx.doi.org/10.1021/cr04042875 DOI]Citations|PalmerMassi06}}

The offset is in In the literature noted , the values are often stated as $\Omega_S$"offset", "carrier offset", where $\Omega_S$ is "offset of the (Exspin-lock pulse" with values given in Hz, and can have values from 0-500 to 10-20.000 Hz. $^{15}$N) resonance <br>These values reflects offset from frequencies to the spincarrier frequency, and in relax is noted as '''"Spin-lock carrieroffset, the frequency of of the rf field"''' : {{:omegarf}}.

Note that $\Omega_S$ is dependent of Relax needs input for {{:omegarf}} in ppm, and during calculations converts to the rad/s, with the following function call.<source lang="python">offsets[ei][wikipedia:Chemical_shift | chemical shiftssi][mi][oi]= frequency_to_rad_per_s(frq=cdp.spin_lock_offset[id] $\delta$ in ppm for the nuclei of interest, and is first calculated laterB0=frq, isotope=spin.isotope)</source>

In the literature, the If you need to convert to ppm from Hz values are often stated as "offset", "carrier offset", "offset of the spin-lock pulse" with values given consider during this in Hz, and can have values from 0-500 to 10-20.000 Hzyour relax script.<br>These values reflects offset frequencies to If for example you have recorded at a 800 MHz spectrometer, you could find the carrier frequencyCarrier position for ¹⁵N (Value of yCar in NMRPipe scripts). If yCAR = 118.078 ppm, and in relax is noted as '''then<source lang="python"Spin-lock offset>from lib.nmr import frequency_to_Hz, the frequency_to_ppm # Spectrometer frequency of of the rf field"''' : $\mathbf{\omega_{rf}}$sfrq = 799.7773991 # MHz# Carrier positionyCAR = 118.078 # ppm

Relax needs input for $\mathbf{\omega_{rf}}$ in ppm, and converts to the rad/s, with the following function callsrelax_disp.<source lang="python">offsets[ei][si][mi][oi] = frequency_to_rad_per_sspin_lock_offset(frqspectrum_id=cdp.spin_lock_offset[id]sp_id, B0offset=frq, isotope=spin.isotopeyCar_offset_ppm)

=== spin lock field ===The spin lock field strength is noted '''$\nu_1$Offset in the literature'''<br> The offset is in the literature noted as Ω_S, where Ω_S is the (Ex.<brsup>15</sup>N) resonance offset from the spin-lock carrier. Note that Ω_Sis dependent of the [[wikipedia:Chemical_shift | chemical shifts]] δ in ppm for the nuclei of interest. The [[wikipedia:Chemical_shift | Chemical Shifts]] $\delta$ δ in ppm for nuclei of interest (ex. $^{^15}$N and which have been loaded in with relax function [http://www.nmr-relax.com/manual/chemical_shift_read.html chemical_shift_read] from a [http://www.nmr-relax.com/manual/spectrum_read_intensities.html peak list formatted file]) is first converted to to the rad/s with the following function calls. <math>\bar{\omega}_{S,i} = 2\pi \cdot \delta_{S,i} \cdot B_0 \cdot \frac{\gamma_{^{15}N}}{\gamma_{^{1}H}}</math> 

Then $\Omega_S$ <span style="text-decoration: overline">Ω_S</span> is calculated with: $\Omega_{<span style="text-decoration: overline">Ω_S,i}</span> = <span style= \bar{\omega}_{"text-decoration: overline">Ω_S,i}</span> - \omega_{rf{:omegarf}}$, where $\bar{\omega}$ <span style="text-decoration: overline">Ω</span> is the population averaged Larmor frequency of the spin and comes from the conversion of the [[wikipedia:Chemical_shift | Chemical Shifts]] $\delta_{δ_S,i}$ to frequency $\bar{\omega}_{<span style="text-decoration: overline">Ω_S,i}$</span>.

=== spin lock field ===The spin lock field strength is noted {{:nu1}}, and relax requires these to be provided in unit of '''rad/s'''.<br> The trouble spin lock field strength is converted to rad/s, with the following function call. <math>\omega_{S,1} =2\pi \cdot \nu_{S,1}</math> <source lang="python">omega1 =point * 2.0 * pi</source> The trouble Then the Rotating frame tilt angle θ iscalculated.

At page 1708 <source lang="python">if Delta_omega == 0.0: theta[ei][si][mi][oi].append(pi / 2.0)# Calculate the theta angle describing the tilted rotating frame relative to the laboratory.# If Delta_omega is states negative, there follow the symmetry of atan, that w_1S atan(-x) = - atan(x).# Then it should be: theta = w_1 and w_eS pi + atan(-x) = w_epi - atan(x) = pi - abs(atan( +/- x))elif omega1 / Delta_omega > 0 : theta[ei][si][mi][oi].append(atan(omega1 / Delta_omega))And in pulse sequence it states thatelse: theta[ei][si][mi][oi].append(pi + atan(omega1 / Delta_omega))</source>

[[Category:Relaxation_dispersionRelaxation dispersion analysis]]