Figure 1.

(a) Pulse sequence for the frequency-swept integrated solid effect. ¹H signals are detected with a solid echo. (b) During the sweep, the spin system undergoes three adiabatic events including DQ and ZQ at A and B, respectively, as well as electron spin inversion at O. The semicircle represents the relationship ${\omega }_{0I}^2={\mathrm{\Omega }}^2+{\omega }_{1S}^2$, which is satisfied at A and B where Ω is the microwave frequency offset. The inversion leads to the constructive addition of DNP enhancement at A and B, thus the name integrated solid effect.