Trifurcation of the reaction pathway

A concept of trifurcation of a reaction pathway is introduced to analyze the case where a downhill path from the first-order saddle point accompanies three branches via the valley–ridge inflection region, leading to three different product minima on the potential energy surface. We provide a detailed analysis on the reaction path for an electron transfer reaction, HCHO− + CH3Cl → OH2C–CH3…Cl−, as an illustrative example of the trifurcating reaction path.