Table 1.

¹H spin-lattice relaxation times and the fitting parameters of the buildup curves

Sample*	$T_{1n}^{\mathrm{†}}$	$T_{1\mathrm{laser}}$	$T_{1e}$	${\frac{dP\left(t\right)}{dt}|}_{t=0}$	$P_{\mathrm{fin}}$	τ
Unit	min	min	min	%/min	%	min
ThPh	11	6.0	13.2	5.8	14	2.4
TdPh	37	10.6	14.9	5.5	16	2.9
ThPd	11	7.3	21.7	5.5	18	3.3
TdPd	37	18.9	38.6	5.5	34	6.2

^*The denotation is the same as in Fig. 2.

^†The relaxation times $T_{1\mathrm{laser}}$ and $T_{1n}$ were measured with and without the pulsed laser irradiation at the repetition rate of 50 Hz, respectively. $T_{1e}$ is the electron contribution in $T_{1\mathrm{laser}}$. The initial gradient ${dP\left(t\right)/dt|}_{t=0}$ of the polarization buildup curve, fitted by $P\left(t\right)=P_{\mathrm{fin}}\left(1-e^{-t/\tau }\right)$, was calculated by $P_{\mathrm{fin}}/\tau$.