Trajectory analysis is vital for several reasons: 1. Reaction Mechanisms: It helps in understanding the step-by-step process of how reactants convert to products. 2. Energy Barriers: Identifies the energy barriers that need to be overcome for a reaction to proceed. 3. Intermediate States: Discovers intermediate species that may exist transiently during the reaction. 4. Catalyst Design: Provides information that can be used to design more effective and selective catalysts.