Fig. 6. Transient nutation of the quintet state at room temperature.

(A) Pulse sequence of the transient nutation measurement. (B) Two main quantum gates detected by the pulsed microwave at B₀ = 348.1 mT in the quintet sublevels. (C) Echo-detected EPR spectrum at τ_delay = 1.1 μs. The durations of the first and second pulses are x = 8 ns and t₂ = 16 ns, respectively. Fitting result using eq. S15 and table S5 is shown as a red line. (D) Transient nutation profiles as a function of x in (A) at τ_delay = 1.1 μs using t₂ = 16 ns. The simulated profile is shown by a red line considering the anisotropic sublevel populations. At the bottom, decomposition of the computed nutation data by the gates Q_0,±1 and Q_±2,±1 are shown by purple and green lines, respectively. (E) Simulated profiles by the different rotation models. The red solid line corresponding to the red line in (D) is computed by the conformation motion between the dihedral angles of β = 130° and 122° of the T_B molecule in the T_AT_B pair for TT₁ and TT₂, respectively. Green dashed line is obtained with considering the large dihedral angle change between β = 130° and 150° in Fig. 4B. (F) Dependence of τ_delay on the echo intensity (black line) employing x = 8 ns, t₂ = 16 ns, and τ_echo = 200 ns with B₁ = 0.45 mT together with delay time dependence of the CW-TREPR intensity at 351 mT in Fig. 4A (blue line). Fitting result using eq. S1 and table S5 is shown as a red line.