Figure 14.

Dependence of on-resonance R_1ρ on exchange and spin-lock parameters.A) Δω and ω₁ modulate R_ex via changes in φ, the angle between ω_eff,GS and ω_eff,ES. Also shown are positions of the magnetization vectors corresponding to GS (blue circles) and ES (red circles) obtained using vector model simulations in the form of Sanson-Flamsteed projections[192]. ω_eff,GS and ω_eff,ES are indicated by black and red stars respectively. Simulations were performed with the following parameters - p_ES = 0.01, k_ex = 20,000 s⁻¹, $\Delta \overline{\omega }{(}^{13}\text{C)}=3\text{\hspace{0.17em}ppm}$, γ(¹H)B₀/2π = 700 MHz, ω₁/2π = 1000 Hz when on-resonance with the AVG state. Positions of the spins for a larger $\Delta \overline{\omega }{(}^{13}\text{C)}=10\text{\hspace{0.17em}ppm}$ (right) and ω₁/2π = 3000 Hz (left) are also shown. Simulations employed 10,000 spins with a relaxation delay of 0.012s.B) Variation of R₂ + R_ex with ω₁ under on-resonance conditions as a function of exchange parameters, as obtained using B-M simulations. Rows and columns correspond to the indicated values of k_ex and p_ES, respectively. Dashed line denotes the value of R₂. The other exchange parameters used were $\Delta \overline{\omega }{(}^{13}\text{C)}=3\text{\hspace{0.17em}ppm}$, γ(¹H)B₀/2π = 700 MHz, R_1,GS= R_1,ES = 2.5 s⁻¹ and R_2,GS = R_2,ES = 22.5 s⁻¹. The initial alignment of the magnetization during the B-M simulations was performed as described in Section 6.1.