Luminescence bands of molecular oxygen from a tungsten lamp.: The possible role of singlet molecular oxygen in surface catalyzed oxidation
✍ Scribed by Ahsan Ullah Khan
- Publisher
- Elsevier Science
- Year
- 1970
- Tongue
- English
- Weight
- 254 KB
- Volume
- 4
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Sharp emission bands superimposed on ordinary incandescent tungsten lamp output have been observed. These definite spectroscopic bands have been tentatively assigned to Single and Simultaneous Transitions in molecular oxygen. An alternative explanation of a perturbed molecular oxygen, [W.. _ 021. has not been completely ruled out. A possible relation of this novel method of generation of Singlet Molecular Oxygen to heterogeneous catalysis has been pointed out.
We wish to report the generation of electronically excited molecular oxygen in ordinary incandescent tungsten filament lamps. Using these lamps, we have not only observed emission from the singlet metastable states of molecular oxygen, but : I TO from simultaneous transitions in which two 9 *', excited singlet species interact to yield a sing,, photon.
Recently McCarroll [l] reported that the chemisorption on a clean tungsten surface at room temperature of molecular oxygen at 5 -50& pressure generates a very weak luminescence. He studied the lifetime and the kinetics of decay for this luminescence by using a refrigerated 9558QB photomultiplier and narrow band interference filters and found that "most of the luminescent radiation is distributed between 520 and 560 run with some emission between 560 and 620 run, approximately",
We have observed these two emissions as definite spectroscopic bands, which appear strongly in our tungsten lamp emission spectra, and have observed in addition several other transitions. We believe that all these transitions originate in molecular oxygen which is present in the incandescent lamp as an impurity and is used cyclically to elicit the observed emission. We believe that the two bands recorded by McCarroll are due to simultaneous * This work was supported by a contract between the Division of Biology and Medicine, 75. S. Atomic Energy Commission and the Florida State University.