Singlet delta oxygen (O2(a 1Δg)), the first electronically excited state of O2, plays an important role in many applications. We report the first measurements of absolute densities of O2(a 1Δg) in an atmospheric pressure plasma jet (APPJ) by molecular beam mass spectrometry (MBMS). The ability to measure axial and radial profiles of O2(a 1Δg) impinging on a substrate in the effluent of the APPJ is a key advantage of the MBMS diagnostic method over previously reported optical methods. The measured large O2(a 1Δg) densities in the APPJ effluent, up to one order of magnitude higher than the O density, underline the potential importance of O2(a 1Δg) in many applications using APPJs.
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- Absolute density
- Molecular beam mass spectrometer
- Singlet delta oxygen