Mercury-photosensitized reactions in the presence of CO: decomposition of ethylenimine

1967 ◽  
Vol 45 (14) ◽  
pp. 1685-1691 ◽  
Author(s):  
A. Jones ◽  
F. P. Lossing
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Dissociation Process ◽  
Decomposition Products ◽  
Electronically Excited ◽  
Co Addition ◽  
A Minor ◽  
Triplet Excited States ◽  
Direct Attack ◽  
Primary Interaction

The effect of CO addition on a number of Hg(3P1) photosensitized decompositions, under conditions of incomplete quenching, has been investigated. Compounds having large quenching cross sections (i.e. those presumably decomposing through formation of triplet excited states) have enhanced rates of decomposition in the presence of CO. Those having small cross sections (i.e. those for which the primary interaction is presumably the direct attack of Hg(3P1) atom on a C—H bond) show no enhancement. This difference in behavior, which is interpreted in terms of activation by a HgCO* complex, suggests that CO addition under the appropriate conditions can be used to decide whether or not certain decomposition products aries from an electronically excited precursor. For example, the effect of CO on the sensitized decomposition of ethylenimine indicates that the major dissociation process to form C2H4 and the NH radical proceeds by way of an electronically excited precursor, while a minor process (5%) to form [Formula: see text] radical and a H-atom does not. Some results on the sensitized decomposition of formaldehyde are also discussed.

Dynamics of the KrF* Laser Multiphoton Dissociation of a Series of Arene Chromium Tricarbonyls

1988 ◽  
Vol 131 ◽  
Author(s):  
George W. Tyndall ◽  
Robert L. Jackson
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Dissociation Process ◽  
Parent Molecule ◽  
Electronically Excited ◽  
Arene Ligand ◽  
Multiphoton Dissociation ◽  
Sequential Absorption ◽  
The One ◽  
Direct Dissociation

ABSTRACTThe KrF* (248 nim) laser multiphoton dissociation (MPD) of a series of (arene)chromium tricarbonyls has been investigated in the gas-phase using emission spectroscopy to detect the excited state photoproducts. In the MPD of all compounds studied, chromium atoms are formed in a variety of electronically excited states via a two-channel dissociation mechanism. The predominant pathway for formation of the ground electronic state and the lowest excited states is by a sequential absorption/fragmentation process, where the product of the one-photon dissociation of the parent molecule absorbs an additional photon and dissociates to Cr(I). The higher energy Cr(I) states are formed exclusively by a direct dissociation process, where the parent absorbs multiple photons prior to dissociation. The distribution of excited chromium atoms formed in the direct channel is statistical for all compounds studied and is independent of the nature of the arene ligand. In contrast, the distribution of Cr(I) states formed via the sequential dissociation channel is strongly dependent on the vibrational density of states in the arene ligand.

Charge transfer from low-lying excited states: effects on reactive thermal conductivity

1975 ◽  
Vol 14 (2) ◽  
pp. 365-371 ◽  
Author(s):  
M. Capitelli
Keyword(s):  
Thermal Conductivity ◽  
Charge Transfer ◽  
Excited States ◽  
Cross Sections ◽  
Nitrogen Plasma ◽  
Total Thermal Conductivity ◽  
A Minor ◽  
And Diffusion ◽  
Thermal Conductivity Λ ◽  
Minor Extent

Charge transfer and diffusion cross-sections of low-lying excited states are calculated usingab initioquantum-mechanical potential-energy curves. These data are used to calculate the reactive thermal conductivity λRof an atmospheric nitrogen plasma. Differences of up to 20 % are found between the present values of λRand the corresponding values obtained by increasing the cross-sections of excited states by a factor of 2. These differences propagate, to a minor extent (10 %), in the total thermal conductivity.

Collision integrals of electronically excited states and transport coefficients of thermal plasmas

1974 ◽  
Vol 12 (1) ◽  
pp. 71-79 ◽  
Author(s):  
M. Capitelli ◽  
U. Lamanna
Keyword(s):  
Thermal Conductivity ◽  
Excited States ◽  
Cross Sections ◽  
Hydrogen Plasma ◽  
Transport Coefficients ◽  
Hydrogen Atoms ◽  
Collision Integrals ◽  
Electronically Excited States ◽  
Temperature Range ◽  
Electronically Excited

Collision integrals of excited hydrogen atoms were calculated in the temperature range 10000–25 000 ˚K. These values were used for calculating the viscosity and έ the contribution of the heavy components λH to the translational thermal conductivity of a LTE hydrogen plasma. The results show a dependence of έ and λH on the calculated transport cross-sections.

Lebensdauern und Löschquerschnitte elektronisch angeregter Zustände von N2O+, NO, O2+, CO+ und CO

1968 ◽  
Vol 23 (3) ◽  
pp. 358-376 ◽  
Author(s):  
E. H. Fink ◽  
K. H. Welge
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Independent Method ◽  
Decay Rates ◽  
Electronically Excited States ◽  
Shift Method ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
Air Fluorescence ◽  
Phase Shift Method

Radiative lifetimes of electronically excited states of N2O+, NO, O2+, CO+, and CO are measured by means of the phase-shift method. Excitation is performed by a modulated electron beam. Phase references are derived from He I, N2+, and CO+ transitions as well as from another independent method based on the very short decay time of the air fluorescence.Measurements are performed on the transitionsN2O+ (B2 ∑u+ ➝ X2 IIg), NO (A2 ∑+ ➝ Χ2 II), O2+ (b4 Σg- ➝ a4 IIu),O2+ (A2 IIu ➝ X2 IIg), CO+(B2 ∑ ➝ X2 ∑), CO+ (B2 ∑ ➝ A2 II) ,CO+ (A2 II ➝ X2 ∑), CO (b3 ∑+ ➝ a3 II), CO (B1∑+ ➝ A1 II).As far as feasable lifetimes of individual vibrational levels are measured. From the pressure dependence of the decay rates cross-sections for the quenching of the excited states by the parent molecules are obtained.

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