A Quantitative Study of Some Photochemical Effects Produced by Ultra-Violet Light

Mathews, J. Howard; Dewey, Leon H.

doi:10.1021/j150138a003

Cited by 25 publications

(12 citation statements)

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“…The permanganate anion, MnO 4 - , is a very common inorganic anion in solutions and solids and is extensively used as an oxidizing agent . Its photochemical decomposition with evolution of molecular oxygen in alkaline aqueous solutions was been observed a long time ago . Subsequent studies , have confirmed the evolution of O 2 during the MnO 4 - decomposition and provided order-of-magnitude estimates of its quantum yield.…”

Section: Introductionmentioning

confidence: 79%

“…1 Its photochemical decomposition with evolution of molecular oxygen in alkaline aqueous solutions was been observed a long time ago. 2 Subsequent studies 3,4 have confirmed the evolution of O 2 during the MnO 4decomposition and provided order-of-magnitude estimates of its quantum yield. Using isotopic labels, Zimmerman 5 concluded that all the molecular oxygen that evolved was derived from the photodecomposition of permanganate and not from the solution.…”

Section: Introductionmentioning

confidence: 87%

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Photodecomposition of MnO₄^-: A Theoretical Study

1999

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The electronic and geometrical structures of the ground states and low-lying isomers of MnO 4 and MnO 4 -have been calculated as a function of spin-multiplicities by using the molecular orbital theory based on generalized gradient approximation to the density functional formalism. Total energies of isomers are used for evaluating the energetics of the MnO 4 -decay through various fragmentation channels. Two primary channels were found depending on the energy of photons. The preferred photofragmentation channel, accessible with ≈2 eV photons, is found to involve an initial excitation of the ground-state MnO 4 -anion into its peroxo isomer followed by subsequent excitations into a superoxo form. Photodetachment of an extra electron from this superoxo isomer anion leads to the formation of a neutral superoxo isomer of MnO 4 , which, in turn, dissociates to MnO 2 + O 2 . Excitations of the anion peroxo isomer into biperoxo isomer are also possible with 3.7 eV, photons and the latter could dissociate spontaneously to MnO 2 -+ O 2 . A number of other decay channels are accessible with low-energy photons, but their intensities are expected to be low because these require flipping the spin of one or more electrons.

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Section: Introductionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 87%

Photodecomposition of MnO₄^-: A Theoretical Study

1999

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“…The potential barrier between the permanganate and the peroxo complexes is due to the avoided crossing of the two 1 Ai states and corresponds to the symmetry barrier as mentioned above. Since the HF method cannot well describe this avoided crossing, the potential curve of the HF calculations has a cusp at the barrier.…”

Section: Discussionmentioning

confidence: 99%

“…showed that atomic oxygens like O and 0" are not produced by this photodecomposition reaction, since hydrogen is not extracted from the solvent alcohols. Furthermore, for the lack of an ESR signal corresponding to the 02" anion, they concluded that the photodecomposition reaction proceeds through the formation of a molecular 02 species as Mn04_ -* Mn02" + 02 (1) Lee et al 4 examined experimentally the photodecomposition process of the permanganate ion and showed an existence of a long-lived, highly oxidative intermediate, which is considered to be the Mn(V) peroxo complex. They proposed a photochemical reaction scheme, Scheme 1, including this intermediate.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on the Photochemical Decomposition Reaction of Permanganate Ion, MnO4-

1995

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“…4 Its photochemical decomposition with evolution of molecular oxygen in alkaline-aqueous solutions has been observed long time ago. 5 Although the bulk manganese oxide is antiferromagnetic, Mn x O y clusters have been found to exhibit ferromagnetic or ferrimagnetic behavior. In addition, stoichiometric manganese oxide clusters (MnO) n have been found to possess giant magnetic moments which are localized primarily at Mn sites.…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical study of the photoelectron spectra of MnOx−(x=1–3) clusters

Gutsev

Rao

Jena

et al. 2000

The Journal of Chemical Physics

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We report a combined experimental and theoretical investigation of MnO x Ϫ and MnO x (xϭ1-3) clusters. Theoretically, geometrical configurations of various isomers of the clusters were optimized and vertical detachment energies for the anions were evaluated. The ground state of MnO Ϫ was predicted to be 5 ⌺ ϩ , followed by an excited state (7 ⌺ ϩ) 0.14 eV higher in energy. The ground state of MnO 2 Ϫ is 5 B 2 , with a 3 B 1 isomer 0.15 eV higher. MnO 3 Ϫ is predicted to be a singlet D 3h cluster. Vibrationally resolved photoelectron spectra of MnO x Ϫ were measured at several photon energies and under various experimental conditions, and were interpreted based on the theoretical results. The electron affinities of MnO, MnO 2 , and MnO 3 were determined to be 1.375 ͑0.010͒, 2.06 ͑0.03͒, and 3.335 ͑0.010͒, respectively. Five excited states of MnO were observed and assigned using the theoretical results. The 7 ⌺ ϩ excited state of MnO Ϫ was found to be significantly populated and was distinguished from the ground state of the anion by temperature dependent studies. We observed two isomers for MnO 2 Ϫ and the detachment features from both isomers were assigned. Only one vibrationally resolved band was observed for MnO 3 Ϫ , which corresponds to transitions from the ground state of MnO 3 Ϫ to that of MnO 3. The combined experimental and theoretical studies allow us to elucidate the complicated electronic and geometric structures of the various manganese oxide clusters and their anions.

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A Quantitative Study of Some Photochemical Effects Produced by Ultra-Violet Light

Cited by 25 publications

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Photodecomposition of MnO₄^-: A Theoretical Study

Photodecomposition of MnO₄^-: A Theoretical Study

Theoretical Study on the Photochemical Decomposition Reaction of Permanganate Ion, MnO4-

Experimental and theoretical study of the photoelectron spectra of MnOx−(x=1–3) clusters

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A Quantitative Study of Some Photochemical Effects Produced by Ultra-Violet Light

Cited by 25 publications

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Photodecomposition of MnO4-: A Theoretical Study

Photodecomposition of MnO4-: A Theoretical Study

Theoretical Study on the Photochemical Decomposition Reaction of Permanganate Ion, MnO4-

Experimental and theoretical study of the photoelectron spectra of MnOx−(x=1–3) clusters

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Product

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Photodecomposition of MnO₄^-: A Theoretical Study

Photodecomposition of MnO₄^-: A Theoretical Study