FTP, name this point in a reaction, the structure of which is the activated complex.
These correspond to first-order saddle points on reaction coordinate-potential surfaces, so they can be located by optimizing the potential energy of the corresponding quantum system. Positronium acts as one of these for the annihilation reaction of anti-electrons. For an Arrhenius reaction, the rate is proportional to the negative exponential of the enthalpy required to form it, which is known as the activation energy. Often denoted with a star to indicate that it is energetic, ideal irreversible reactions always go to completion on reaching it, and its structure resembles that of the reaction species closest to it in free energy according to the Hammond postulate. FTP, name this point in a reaction, the structure of which is the activated complex.
These correspond to first-order saddle points on reaction coordinate-potential surfaces, so they can be located by optimizing the potential energy of the corresponding quantum system.
transition state (accept activated complex before it's mentioned)