This requires the knowledge of the intrinsic oscillator strengths of the 3.3 μm aromatic C-H stretch (A3.3) and the 3.4 μm aliphatic C-H stretch (A3.4).

Its aliphatic counterparts, such as cyclohexane (C 6 H 12), are also ring-shaped. However, by contrast with aromatics, they are flexible and thus form a zigzag-like, three-dimensional structure.