Aromatic infrared bands (AIBs) in our laboratory soot samples. a) ω_c(sp³ defect) versus ω_c(L1). b) ω_c(arom. C=C stretch.) versus ω_c(L1). The laboratory found band positions for the sp³ defect and aromatic C=C band are compared to the classification of AIBs by (Peeters et al. 2002). Our laboratory samples are classified as Class B and Class C AIBs. The inferred CSM UV bump carriers fall within Class B/C, and the ISM UV bump carriers approaches the A/B class.