Abstract
Ultraviolet light amplification by the phosphorous chemiluminescence flame is observed in the 200–400-nm region. PO γ-system emission is identified in the light amplification spectrum. Gaps in the amplification spectrum are attributed to the forbidden transitions: 4II→X2II of PO at 30 590 cm−1 and 5Γ1→1,3Γ0 of PO excimer at 28 117 cm−1. Light amplification by the phosphorus chemiluminscence system is interpreted as an incipient lasing action.