Fig. 5.

Calculated relaxation rate constants a) for T_1ρ,on, T_1ρ,E, T_1ρ,off, T_RAFF, T_1ρ,adiab, T_RAFF, T_1ρ,off, and T₁ methods; and b) for T₂, T_2ρ,adiab, T_2ρ,off, T_2ρ,E, T_2ρ,on, and T_RAFF methods. Inserts show expanded views for short τ_c range. The value of R_RAFF was estimated using Bloch simulation, whereas R_1ρ,E and R_2ρ,E were obtained using Eqs. [19] and [20], respectively. The other curves in the figure were calculated using the dipolar relaxation model based on reference (32). On- and off-resonance cw spin-lock were calculated with ${\omega }_1^{max}/(2\mathrm{\pi })=625\text{Hz}$ and additionally Δω/(2π) = 625 Hz (α = π/4) for off-resonance spin lock. The pulse modulation functions given in reference (20) were used for calculating R_1ρ,adiab and R_2ρ,adiab curves with pulse length = 3.0 ms and ${\omega }_1^{max}/(2\mathrm{\pi })=2.5\text{kHz}$ in a similar manner to that in Refs. (10,11). In all calculations, μ₀ = 4π·10⁻⁷, ħ =1.0546·10⁻³⁴ Js, γ =2π·42.58·10⁶ rad/(sT), r = 158 pm and B₀ = 4.7 T were used.