For some time, a unique excited state of the oxygen molecule has been known to have a relatively long half life. The excitation energy of this species is approximately 1 electron volt, and the half life about 40 minutes. This species has been used as an energy source for Iodine/Oxygen chemical lasers. This species is known in the prior art as "Delta Singlet Oxygen" (see for instance "Chemically Pumped Iodine Laser", by R. J. Richardson and C. E. Wiswall, Appl. Phys. Lett. 35(2), July 1979).
This species can be used to stabilize oxygen content in certain high temperature oxide ceramic superconducting layers and in accurate "milling" of diamond-like carbon insulating layers by plasma etching in which "Delta Singlet Oxygen" is the reactive gas.
"Delta Singlet Oxygen" is formed in the following reaction: EQU H.sub.2 O.sub.2 +2KOH+Cl.sub.2 (1)=O.sub.2 (1)+2KCl+H.sub.2 O
In principle, any other hydroxide of the alkali metals (particularly NaOH, see Richardson et. al.) could be used as well, but at the high concentrations required to obtain an efficient "Delta Singlet Oxygen" production rate, potassium hydroxide had been determined to be most suitable, due to the lower viscosity of the solution and thus the ease of atomization.
In the prior art, the combination of hydrogen peroxide with potassium hydroxide in solution was used as the working medium into which chlorine gas was simply bubbled. "Delta Singlet Oxygen" was collected above this solution. This technique, often termed the "bubbler reactor", has had a number of major shortcomings.
The flow rate of chlorine is strongly limited, since too high a flow rate produces unreacted chlorine that can be deleterious (if not for Iodine/oxygen lasers, certainly for the purpose of depositing and etching superconducting electronic devices). Furthermore, excessive eruption of unreacted chlorine drastically disrupts the surface of the liquid and causes excessive interaction of the solution with the already created "Delta Singlet Oxygen". Obviously, this causes premature deactivation of the "Delta Singlet Oxygen".
In a typical bubbler, "Delta Singlet Oxygen" bubbles created near the interaction zone of the chlorine with the hydroxide and peroxide must travel to the top of the liquid. If the flow rate of the chlorine is very slow, then the bubbles are small and the surface area large. This results in deactivation due to contact with the liquid. If the bubbles are too large, the reaction rate is slow and some free chlorine will reach the surface. Decreasing the column of liquid above the bubbling source is not helpful either, since this action results in a decrease of the reaction path. Drip reaction on wet columns is also part of the prior art, and it's major shortcoming is low yield due to the small available surface area.
I have found a novel approach that can be implemented in a number of ways. The principle of the success of said approach lies in the fact that "Delta Singlet Oxygen" is formed at liquid/gas interfaces, and never travels through the column of liquid which could deactivate the excited state prematurely.