Singlet oxygen

Singlet oxygen is an electronically excited form of molecular oxygen whose outer electrons have opposite spins. Its altered electronic structure makes it more reactive than ground-state triplet oxygen.

Triplet oxygen: The ground-state form of molecular oxygen, with two unpaired electrons whose spins are parallel. Its parallel-spin electrons distinguish ordinary oxygen from singlet oxygen’s paired-spin excited states.
Photodynamic therapy: A treatment that combines a photosensitizing drug, light, and oxygen to damage targeted tissue. Many photosensitizers treat tumors partly by producing singlet oxygen near illuminated cells.
Molecular orbital theory: A model of chemical bonding that describes electrons as occupying orbitals spread over a molecule. It explains oxygen’s electronic configurations and why its ground state has unpaired electrons.
Lipid peroxidation: The oxidative degradation of lipids, especially unsaturated fatty acids. Singlet oxygen can initiate lipid oxidation in membranes and food oils.
Oxygen singlet states: The excited electronic states of molecular oxygen in which its two outer electrons have opposite spins. The two lowest singlet states differ in energy and electronic configuration, shaping reactivity.
Photodynamic inactivation: The light-activated use of photosensitizers to inactivate microorganisms through oxidative damage. Singlet oxygen damages microbial membranes and other cellular targets in this disinfection approach.
Spin quantum number: A quantum number describing an intrinsic angular-momentum property of particles such as electrons. Electron-spin orientations distinguish triplet oxygen from singlet oxygen.
Oxidative stress: A state in which oxidant production overwhelms or disrupts biological antioxidant defenses. Singlet oxygen is one reactive oxygen species that can contribute to oxidative damage.
Photosensitization: A process in which a light-absorbing sensitizer transfers energy or electrons to another molecule. Energy transfer from an excited sensitizer is a common route to singlet oxygen.
Photooxidation: An oxidation reaction initiated or accelerated by light. Singlet oxygen drives photooxidation of organic compounds in air, water, and materials.

Linked from 11 pages