Generation of reactive oxygen species in water under exposure to visible or infrared irradiation at absorption bands of molecular oxygen

Heat-induced formation of nitrogen oxides in water

“…It was supposed [16,18,20] that the physicochemical mechanism of the transformation of the heat energy into highly energetic processes leading to the cleavage of chemical bonds and the formation of radical products is the adiabatic collapse of gaseous nanobubbles of atmospheric air contained in the solution [42], as it occurs by the action of ultrasound [43]. The triggering of the collapse of nanobubbles may result from a local electromagnetic perturbation induced by the transition of oxygen into a singlet state [20]. It is known that the temperature and pressure inside a collapsing bubble are sufficient to overcome the energy threshold (E a = 941.4 kJ/mol) of the break of triple bonds in the nitrogen molecule [44].…”

“…The impact of light was demonstrated to have a resonance character because radiations beyond the absorption bands of molecular oxygen did not lead to the formation of ROS in water [20]. It was supposed [16,18,20] that the physicochemical mechanism of the transformation of the heat energy into highly energetic processes leading to the cleavage of chemical bonds and the formation of radical products is the adiabatic collapse of gaseous nanobubbles of atmospheric air contained in the solution [42], as it occurs by the action of ultrasound [43]. The triggering of the collapse of nanobubbles may result from a local electromagnetic perturbation induced by the transition of oxygen into a singlet state [20].…”

“…Thus, in a relatively simple chemical system, as is bidistilled water with dissolved atmospheric gases, thermal energy initiates a number of successive and parallel chemical reactions that lead to the formation of nitrogen oxides. It was shown earlier that the exposure of water to heat [16][17][18][19] and visible light [17,20], including laser irradiation [20], results in the formation of ROS. The impact of light was demonstrated to have a resonance character because radiations beyond the absorption bands of molecular oxygen did not lead to the formation of ROS in water [20].…”

“…It was shown earlier that the exposure of water to heat [16][17][18][19] and visible light [17,20], including laser irradiation [20], results in the formation of ROS. The impact of light was demonstrated to have a resonance character because radiations beyond the absorption bands of molecular oxygen did not lead to the formation of ROS in water [20]. It was supposed [16,18,20] that the physicochemical mechanism of the transformation of the heat energy into highly energetic processes leading to the cleavage of chemical bonds and the formation of radical products is the adiabatic collapse of gaseous nanobubbles of atmospheric air contained in the solution [42], as it occurs by the action of ultrasound [43].…”

“…We have previously found that the exposure of air-equilibrated water solutions to heat [16][17][18][19] and light [17,20] results in the formation of reactive oxygen species (ROS); some details of this complex process have been studied and a possible physical nature of this phenomenon has been considered [16,18].…”