More specifically, the transition state conformer search method is carried out through three steps, as shown in Fig. . In the first step (Fig. )), the "confab" module in the Open Babel software is employed to automatically identify the rotatable bonds and the rotation intervals for transition states. In this work, two modifications are made to the obtained rotatable bonds to avoid the Cartesian coordinate variances of the reactive sites. First, if two atoms linked by a certain rotatable bond both belong to the reactive sites, this rotatable bond is deleted. Second, the atomic numbers of the atoms close to the reactive sites need to be written on the left side of the rotatable bond string.