However, the difference between ρ=1.79 and ρ=5.05 seems to be very large.In fact, because the slopes of both are small, it is an acceptable deviation. When X=H and X=CN, respectively, compared with the experimentally determined apparent activation free energy, they are actually in the range of chemical precision. Even considering the influence of such an error, it is impossible to explain the huge difference between the experimental value and the calculated value of the linear free energy relationship of the Clayden rearrangement. Considering the IRC shape described above, we suspect that this may be the effect of the dynamic effect. IRC represents the trajectory of the initial velocity of 0, so the longer the gradual zone in the IRC, the more representative of the trajectory of the system is likely to stay longer in the dynamic intermediate. The rate of reaction in the presence of a dynamic intermediate will deviate from the prediction of the transition state theory due to the longer trajectory. The more stable the dynamic intermediate is, the lower the prediction will be than the transition state theory. As for the case of stable intermediates after the transition state, it is foreseen that the trajectory is longer, and the rate of the total reaction is lower than the rate of the first-step reaction predicted by the transition state theory. When the rates of the three substrates decrease to varying degrees, the Hammett relationship may change: X=H is much lower than X=OMe, which makes the electron-rich region ρ smaller; X=CN is much lower than X=H. , the slope of the electron-deficient zone may become negative(Fig. ).