Diatomic radicals

The total fluorescence intensity saturated around a few hundreds of mJ/cm2 which corresponds to the irradiation condition where the new plasma-like emission was observed. Above this value fluorescence intensity decreased, which is accompanied with the recovery of the relative intensity of excimer emissions. This means that a quite efficient deactivation channel of excitation intensity opens in this energy range, and the contribution of Si -Si annihilation is depressed. This suggests that fragmentation reactions to diatomic radicals are not induced by the annihilation process. Multi-photon absorption processes via the Si states and chemical intermediates should be involved, although no direct experimental result has as yet been obtained. 

In 1978 the experimental investigation of the electron EDM and other PNC effects was further stimulated by Labzowsky et ai. [20, 21] and Sushkov Flambaum [22] who clarified the possibilities of additional enhancement of these effects in diatomic radicals like BiS and PbF due to the closeness of levels of opposite parity in Q-doublets having a Hi/2 ground state. Then Sushkov et ai. [23] and Flambaum Khriplovich [24] suggested the... 

The experiments to search for EDMs in atoms and molecules are carried out using different approaches [40, 6]. The experimental technique depends on the properties of the atoms and molecules used in such an experiment. These properties influence the atomic and molecular sources, resonance region and detector. For example, for diatomic radicals like YbF or PbF the... 

The ground states of the diatomic radicals PbF and HgF are n /2 and Si/2) respectively. Here the superscript denotes spin multiplicity, H and... 

Here, we focus our attention on the interplay that exists between solvation processes and ultrafast redox reaction in the vicinity of the strong oxidant hydroxyl radical (OH). This diatomic radical represents one of the most efficient oxidant of cellular components (proteins, lipids, DNA), contributes to Haber-Weiss reaction and plays some important role in fundamental radiation or stratospheric chemistry. Presently, we have investigated short-time water caging effect on transient electron delocalization-relocalization in the vicinity of nascent aqueous OH radicals. This specific electronic channel is represented by Eq.(l). 

V-ll. ELECTRONIC TRANSITIONS AND LIFETIMES OF SOME DIATOMIC RADICALS... 

Diatomic radicals are often produced in their ground and electronically excited states as primary photolytic products or as reaction intermediates. 

Reaction rates of diatomic radicals have frequently been studied by following time dependent optical absorption immediately after the radicals... 

Diatomic Radical Slate (eV) System (Region of Absorption) Lifetime Kef-... 

Table A-7. Enthalpies of Formation of Diatomic Radicals at I atm and 0 K in the Ideal Gas State... 

V-l I Electronic Transitions and Lifetimes of Some Diatomic Radicals, 192... 

Rate constants of diatomic radicals such as OH, SH, CIO, and SO with atmospheric constituents arc tabulated in recent publications by Hampson and Garvin (10) and by Anderson (I). In the following section we present the main transitions, lifetimes, and a few reaction rates of some diatomic radicals of photochemical interest. The results arc summarized in Tables V I0A through V-14. 

V—tl. i.k ctronu transitions and Lifetimes oj Some Diatomic Radicals 19V... 

The late 30 s brought a further important step in the investigation of the interstellar medium — the discovery of the first molecular species. In the optical region, the electronic spectra of the diatomic radicals CH, CH+, and CN, seen in absorption against the continuum spectra of bright background stars, furnished the first evidence that the interstellar medium was not devoid of molecules but contained at least some simple ones. However, the intensities of the molecular spectral peaks seen via optical absorption studies were quite weak compared with the spectra of atoms, indicating that the sources observed in these early studies were not rich in molecules. These sources, now labeled diffuse interstellar clouds, possess very low gas densities (n 102 cm-3) and are of limited interest chemically. 

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