 Collision-induced absorption and emission

Collision-induced absorption (CIA) and collision-induced emission (CIE) are phenomena that occur when molecules interact with one another during collisions, leading to changes in their energy states. These processes are particularly relevant in the context of molecular gases and contribute to their spectral properties. Here's a breakdown of each concept: ### Collision-Induced Absorption (CIA) - **Definition**: CIA refers to the absorption of light (electromagnetic radiation) resulting from the interactions between colliding molecules.