Heavy-atom effects in laser properties of 9-acetoxy-10-acetoxyhalogenophenylanthracene derivatives

Laser emission has been found for eight new 9-acetoxy-10-acetoxyhalogenophenylanthracene. For these compounds the absorption threshold power, laser output energy, and lasing region have been determined. It has been found that derivatives possessing –OAc or heavy-atom substituents in position 2′ or 6′ of the phenyl ring show laser properties differing distinctly from those compounds which have them in positions 4′, 3′ or 5′. These differences can be explained throughout by ‘‘internal heavy-atom’’ effects and interaction—hydrogen bonding—of the substituted phenyl ring with the anthracene skeleton. This interaction shifts the triplet levels causing a decrease of T1–Tn absorption losses.