State-selective electron capture

Janev, R. K., Phaneuf, R. A Tawara H. and Shirai, T. (1993) Recommanded cross sections for state-selective electron capture in collisions of C6+and 08+ ions with atomic hydrogen, At. Data and Nucl. Data Tables, 55, pp. 201-232. 

Electron-Ion and Ion-Ion Recombination Processes, M. R. Flannery Studies of State-Selective Electron Capture in Atomic Hydrogen by Translational Energy Spectroscopy, H. B. Gilbody Relativistic Electronic Structure of Atoms and Molecules, I. P. Grant The Chemistry of Stellar Environments,... 

The most common final separation techniques used for agrochemicals are GC and LC. A variety of detection methods are used for GC such as electron capture detection (BCD), nitrogen-phosphorus detection (NPD), flame photometric detection (FPD) and mass spectrometry (MS). For LC, typical detection methods are ultraviolet (UV) detection, fluorescence detection or, increasingly, different types of MS. The excellent selectivity and sensitivity of LC/MS/MS instruments results in simplified analytical methodology (e.g., less cleanup, smaller sample weight and smaller aliquots of the extract). As a result, this state-of-the-art technique is becoming the detection method of choice in many residue analytical laboratories. 

Dubois, A., Nielsen, S.E. and Hansen, J.P. (1993) State selectivity in H+-Na(3s/3p) collisions differential cross sections, alignment and orientation effects for electron capture J. Phys. B, 26, pp. 705-721. 

Direct verification of DR-mechanism of DIET was provided [21] by combining the state-selective photoexcitation of the sample and the controlled thermally induced release of electrons from electron traps (Fig.9a). In RGS, after electron-hole pair creation at selective excitation by photons with energies E>Eg, the hole may survive and be self-trapped if the electron is captured by any kind of traps [32], In solid Ar at T>2 K the main part of electron traps is not active [12], the electron-hole recombination occurs before self-trapping the holes, and, therefore, the concentration of W-band emitting centers decreases (Fig.9a). On the contrary, the heating... 

In this connection it is noteworthy that smooth defluorination of some fluoroquinolones (used as antibacterial drugs) is obtained both at the cathode and by photolysis in the presence of sodium sulfite in aqueous solution, as it is shown for enoxacin (65) in Scheme 47 [142]. The 6,8-difluoro derivative lomefloxacin is selectively defluorinated at position 8 by cathodic reduction. Electron capture of electrons by 5-halouracils in neutral organic and aqueous glasses leads to species characterized as cr radical anions (more advanced in the path towards cleavage) with the iodo and bromo derivatives, whereas n radical anions are formed from the chloro and fluoro derivatives [143]. The radical anion of 2-chlorothiophene (obtained by irradiation in the crystal state) is of the cr type [144]. 

Figure 2.16 Electron capture detector(ECD) (a) and photo-ionization detector (PID) (b). The BCD must be installed in an well ventilated position owing to it containing a radioactive source. The PID contains a UV source from which the photons are emitted, having a pre-selected energy, using a filter which prevents undesired carrier gas ionization M + hv M+ - - e ). Examples of filters LiF at ll.SeV, MgFj at 9.6-10 eV, sapphire at 8.4 eV. On contact with the electrodes the molecules return to uncharged state, ionization being therefore reversible. The use of the make-up gas provides an optimal flow.

NO can be measured by UV absorption. A highly sensitive and selective method is based on reaction of NO with O3 to produce an excited NO9 species that emits radiation in the 590- to 2600-nm range upon returning to the ground state. Nitrous oxide, N2O, is the most abundant oxide of nitrogen in the atmosphere and can be measured by IR absorption or gas chromatography with electron capture detection. 

Since P decay occurs throughout the periodic table, it offers a wider field of study than a decay, which is largely confined to heavy elements. The term P decay encompasses both P (negatron) and P (positron) emission (Curie and JoKot 1934) as well as the process of orbital electron capture discovered in 1937 (Alvarez 1937) which, like P emission, leads to a one-unit decrease in atomic number. In each of the three processes a neutrino is emitted (in P emission it is an antineutrino). The systematic of P decay has been worked out and selection rules for P transitions in terms of spin and parity changes have been established. Many if not most P transitions lead to excited states of the product nuclei. 

ABSTRACT. Calculation of the rate constant at several temperatures for the reaction +(2p) HCl X are presented. A quantum mechanical dynamical treatment of ion-dipole reactions which combines a rotationally adiabatic capture and centrifugal sudden approximation is used to obtain rotational state-selective cross sections and rate constants. Ah initio SCF (TZ2P) methods are employed to obtain the long- and short-range electronic potential energy surfaces. This study indicates the necessity to incorporate the multi-surface nature of open-shell systems. The spin-orbit interactions are treated within a semiquantitative model. Results fare better than previous calculations which used only classical electrostatic forces, and are in good agreement with CRESU and SIFT measurements at 27, 68, and 300 K. ... 

Florida State University tandem accelerator. The accelerated ions were focused onto a 10 pg/cm carbon foil, Foil-1 in fig. 2, placed near the entrance slits of a 90° momentum analysing magnet. Fully stripped ions were selected by the magnet and then passed through a second, nominally 5 pg/cm foil, Foil-2. Here approximately 30% of the ions captured an electron to produce of which... 

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