Optical Absorption of Excimer Laser‐Induced Dichlorine Monoxide in Silica Glass and Excitation of Singlet Oxygen Luminescence by Energy Transfer from Chlorine Molecules

Abstract

An optical absorption (OA) band of interstitial dichlorine monoxide molecules with peak at 4.7 eV and halfwidth 0.94 eV is identified in F2 laser‐irradiated (ħω = 7.9 eV) synthetic silica glass bearing both interstitial O2 and Cl2 molecules. Alongside with intrinsic defects, this OA band can contribute to solarization of silica glasses produced from SiCl4. Although only the formation of ClClO is confirmed by its Raman signature, its structural isomer ClOCl may also contribute to this induced OA band. Thermal destruction of this band between 300 °C and 400 °C almost completely restores the preirradiation concentration of interstitial Cl2. An additional weak OA band at 3.5 eV is tentatively assigned to ClO2 molecules. The strongly forbidden 1272 nm infrared luminescence band of excited singlet O2 molecules is observed at 3–3.5 eV excitation, demonstrating an energy transfer process from photoexcited triplet Cl2 to O2. The energy transfer most likely occurs between Cl2 and O2 interstitial molecules located in neighboring nanosized interstitial voids in the structure of SiO2 glass network.