A physical and chemical investigation of the nature and properties of the species formed in the Hg(6<sup>3</sup>P<sub>1</sub>)–CO system

London, G. B.; Vikis, A.C.; Roy, D. J. Le

doi:10.1139/v70-233

Cited by 8 publications

(7 citation statements)

References 15 publications

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“…These enhancement effects cannot be realized in terms of simple competitive quenching between C,H, and Q since this would cause the S/So curves to lie below the dotted line as in the case of CO,. The effect is attributed to Hg(63Po) formation and we propose the following mechanism (1,14) in which Hg*, HgO, and Hg represent Hg(63P,), Hg(63Po), and Hg(6l So), respectively. Reactions 4 and 10 include all processes, besides radiative decay, which are first or pseudo-first order under our experimental conditions (constant mercury pressure and constant total pressure).…”

Section: Resultsmentioning

confidence: 85%

“…The method of studying Hg(6,P0) formation and decay in the presence of various molecules has been outlined in previous publications (1,14,17). It is based on the enhancement of the mercury photosensitized decomposition of C,H4 under incomplete quenching of Hg(6,P1).…”

Section: Methodsmentioning

confidence: 99%

“…However, there were only few direct measurements such as rate constants for the occurrence of reaction 1. The result of Scheer and Fine (10) for CO has recently been questioned (14, 126).Also, of particular interest were the alkanes which have been thoroughly studied in the past and were shown to exhibit a number of interesting trends (8,9), as far as their reactions with Hg(63P,) are concerned. Qualitative studies of Hg(63Po) formation in these systems were reported by Penzes et al (16) using 4047 A light absorption to monitor ~g(6~P,,) steady state populations.…”

mentioning

confidence: 99%

“…However, there were only few direct measurements such as rate constants for the occurrence of reaction 1. The result of Scheer and Fine (10) for CO has recently been questioned (14, 126).…”

mentioning

confidence: 99%

“…Because of the importance of these measurements in the elucidation of the energy transfer process in mercury photosensitization (2)(3)(4)(5)(6)(7)(8)(9) and the controversial nature of the problem (10)(11)(12)(13)(14), we have investigated the spin-orbit relaxation process in greater detail and extended our measurements to more molecules.…”

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confidence: 99%

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Spin–Orbit Relaxation of Hg(6³P₁) by Various Gases

Vikis¹,

Torrie²,

Roy³

1972

Can. J. Chem.

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The spin-orbit relaxation of Hg(6,P1) to yield Hg(6,P0) was investigated in the presence of various gases. The quantum yields of Hg(6,P0) formation (defined as relaxation to Hg(63Po)/total relaxation) in the presence ofCO, CO,, NH,, ND,, H,O, D,O, C2H6, C(CH,),, C3H,, 2,2-C3H6D2, C3D,, n-C4H,, and i-C4Hlo were: 0.88 + 0.07, <0.01, 1.05 + 0.05, 1.00 k0.08, 0.76 + 0.18, 1.06+ 0.26, 0.64 k0.16, 0.56 40.10, 0.58 +0.02, 0.14+0.01, 0.51 k0.07, 0.47+0.10, 0.11 k0.01, and 0.05+0.01, respectively. The extent of the spin-rbit relaxation process appears to be related in an inverse manner to the availability and accessibility of channels leading to the formation of Hg(6'S0), rather than to the fulfillment of electronic-vibrational resonance conditions. This in turn suggests the existence of Hg(63Pl)--quencher intermediates having lifetimes long enough to permit several vibrations.La relaxation spin-rbitale de Hg(6,P1) pour donner Hg(6,P0) a tte etudike en presence de nombreux gaz. Les rendements quantiques de la formation de H~(~, P , ) (definis par relaxation de H~(~, P , ) sur relaxation totale) en presence de CO, CO,, NH,, ND,, H,O, D,O, C,H6, c-C,H6, C(CH,),, C3H8, 2,2-C3H6D,, C3D8, n-C4Hlo et i-C4Hlo sont: 0.88 + 0.07, 10.01, 1.05 + 0.05, 1.00 + 0.08, 0.76 + 0.18, 1.06 + 0.26, 0.64 + 0.16, 0.56+0.10, 0.58+0.02, 0.14+0.01, 0.51 k0.07, 0.47+0.10, 0.11 k0.01 et 0.05+0.01. Le domaine du procCd6 de relaxation spin orbitale apparait comme ttant en sens inverse de la disponibilite et de I'accessibilitC des canaux menant a la formation de Hg(6'S0) plutBt que du remplissage des conditions de resonance electronique-vibrationnelle. Ceci suggkre I'existence d'intermtdiaires de pitgeage Hg(6,P,) qui ont des temps de vie assez longs pour permettre plusieurs vibrations.Canadian Journal of Chemistry, 50, 176 (1972) In a recent communication from this laboratory (1) we have presented preliminary data on the spin-orbit relaxation of Hg(63Pl) atoms to yield Hg(63Po) in the presence of various gases. Because of the importance of these measurements in the elucidation of the energy transfer process in mercury photosensitization (2-9) and the controversial nature of the problem (10-14), we have investigated the spin-orbit relaxation process in greater detail and extended our measurements to more molecules. Particular attention was focused on molecules such as CO, CO,, H,O, D,O, NH, and ND,, that have been previously considered ( 2 4 , 10, 15) from the point of view of the resonance theory of spin-orbit relaxation,The relative increase of the total ~g ( 6~~, ) quenchingcross section with the relative decrease of the energy discrepancy, AE, of the electronic and the vibrational transition, were cited as basis for the resonance theory. However, there were only few direct measurements such as rate constants for the occurrence of reaction 1. The result of Scheer and Fine (10) for CO has recently been questioned (14, 126).Also, of particular interest were the alkanes which have been thoroughly studied in the past and were shown to exhibit a num...

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Section: Resultsmentioning

confidence: 85%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

“…However, there were only few direct measurements such as rate constants for the occurrence of reaction 1. The result of Scheer and Fine (10) for CO has recently been questioned (14, 126).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Spin–Orbit Relaxation of Hg(6³P₁) by Various Gases

Vikis¹,

Torrie²,

Roy³

1972

Can. J. Chem.

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The mercury‐sensitized oxidation of carbon monoxide

Simonaitis

Heicklen

1971

Int J of Chemical Kinetics

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The mercury‐photosensitized oxidation of CO was studied at 275°C over a wide range of [O2]/[CO] ratios in the absence and presence of the oxygen atom scavenger 2‐trifluoromethylpropene (TMP) and at 25°C at low [O2]/[CO] ratios in the presence of TMP. By following the quantum yield of CO2 production, Φ {CO2}, as a function of the [O2]/[CO] ratio, the reactions of vibrationally excited CO (v υ 9) and electronically excited O2, probably in the c1Σ−u state, were studied. At low [O2]/[CO] ratios the predominant reactions are of vibrationally excited CO (v υ 9). Relative rate constants for chemical reaction versus deactivation of CO (v υ 9) were obtained. At higher [O2]/[CO] ratios, the principal reactions are of electronically excited O2. Relative rate constants for chemical reactions and deactivation of this electronically excited O2 with CO, O2, and TMP were obtained. From the effect of total pressure on Φ {CO2}, it is proposed that an intermediate CO3 is formed in the reaction of electronically excited O2 with CO.

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