XXVI.<i>The absorption band spectrum of selenium</i>

Nevin, T. E.

doi:10.1080/14786443508561484

Cited by 12 publications

(3 citation statements)

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“…Secondly, the 248-nm photolysis of tert -butyl isoselenocyanate , in acetonitrile or Freon-113 produces a transient growth with somewhat longer lifetime, and the absorption maximum lies at 310 nm; this transient is assigned to Se 2 ( 3 Σ g - ). The observed bathochromic shift between S 2 ( 3 Σ g - ) and Se 2 ( 3 Σ g - ) is expected from the known absorption spectra , and, thus, corroborates the proposed chemical reaction sequence for photolysis of isothio- and isoselenocyanates. Further studies on the isoselenocyanate as a source for Se( 3 P J ) atoms were discouraged by a very rapidly developing precipitation on the cell walls, supposedly elemental selenium, which led to severe shock waves in the transient traces, thus obstructing an accurate quantitative analysis.…”

Section: Resultssupporting

confidence: 83%

Absolute Rate Constants for the Reactions of Sulfur (³P_J) Atoms in Solution

1997

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The 248-nm laser flash photolysis of methyl isothiocyanate (MeNCS) was used to generate S( 3 P J ) ground state atoms in acetonitrile solution. The reaction of S( 3 P J ) atoms with the MeNCS precursor produces molecular diatomic sulfur S 2 ( 3 Σ g -) in its ground state, which possesses an absorption at ca. 270 nm. The first-order growth of this absorption was used to monitor the decay kinetics of the sulfur ( 3 P J ) atoms and to measure the rate constants for their reactions with additives. The rate constants obtained for a number of olefins, e.g., 9.7 × 10 7 M -1 s -1 for ethyl vinyl ether, hydrogen donors, e.g., 3.1 × 10 9 M -1 s -1 for tributyltin hydride, sulfur atom donors, e.g., 5.0 × 10 7 M -1 s -1 for carbon disulfide, and nucleophiles, e.g., 1.3 × 10 9 M -1 s -1 for chloride ions, demonstrate that S( 3 P J ) atoms behave as reactive, yet very selective, intermediates in solution; the highest reactivity was observed toward nitrogen and phosphorus nucleophiles, e.g., 1.2 and 2.1 × 10 10 M -1 s -1 for hydrazine and triethyl phosphite. The comparison with known nucleophilicity constants, e.g., for methyl iodide as electrophile, suggests further that S( 3 P J ) atoms act as potent but relatively soft electrophiles. The reaction modes between S( 3 P J ) atoms and the additives are assumed to involve abstractions of single atoms or addition to double bonds or lone electron pairs. The reaction rate constants for atomic sulfur S( 3 P J ) in solution are compared with previous gas phase data for S( 3 P J ) atoms and with the data for oxygen ( 3 P J ) atoms in solution.

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Section: Resultssupporting

confidence: 83%

Absolute Rate Constants for the Reactions of Sulfur (³P_J) Atoms in Solution

1997

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“…Therefore, instead of recording a continuous spectrogram, sampling was made in view of special features of the spectra of selenium atom and Se 2 molecule. Spectrograms were recorded in the regions of 200-220, 323-363, and 450-540 nm, the middle one of which could contain the most intense spectral bands of Se 2 molecule 28], and both extreme ones -SeI spectral lines studied in [22].…”

Section: Results and Their Discussionmentioning

confidence: 99%

Dissociative excitation of selenium atoms in collisions of electrons with Se2 molecules

Smirnov

2006

High Temp

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The dissociative excitation of selenium atom by electron impact is investigated for the first time under conditions of narrow composition of molecular beam. The thermal destruction of heavy Se n molecules is used to obtain a beam with prevailing Se 2 molecule. Seventeen cross sections of dissociative excitation of SeI are measured at electron energy of 50 eV. Possible reactions of formation of excited selenium atoms in e-Se 2 collisions are discussed.

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“…The samarium oxide was dissolved in dilute HN0 3 and was spread uniformly from solution onto 8 jug/cm 2 collodion backing with the aid of insulin. 9 Sources were 4 cm high and 1 or 2 mm wide. Source densities ranged from 0.075 to 0.10 mg/cm 2 which resulted in some distortion of low-energy spectra.…”

Section: Experimental Methodsmentioning

confidence: 99%

Radioactivity ofSm153andEu155

Lee

Katz

1954

Phys. Rev.

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The radiations from Sm 153 and Eu 155 have been studied by means of a 180-degree, magnetic-focusing, variable-field beta-ray spectrometer-spectrograph using enriched materials. In the disintegration of 47.0-hr Sm 153 , conversion electrons of three gamma rays of energy, 0.0691, 0.1027, 0.548 Mev, and three beta-ray spectra whose end-point energy and relative intensity were 0.255 Mev, 9 percent; 0.685 Mev, 70 percent; 0.795 Mev, 21 percent, respectively, were observed. A fourth beta-ray spectrum of end-point energy 0.62 Mev and intensity less than 6 percent is postulated. A decay scheme in good agreement with these data and with nuclear shell theory is proposed in which spin and parity have been assigned to all levels. The discrepancy between the magnetic moment measurement and the requirements of shell theory as to the parity of the ground state of Eu 153 has been resolved in favor of shell theory. In the disintegration of Eu 155 two beta-ray spectra of end-point energy 0.152 and 0.252 Mev and relative intensity 84 percent and 16 percent, respectively, and conversion electrons of four gamma rays of energy 0.0593, 0.0858, 0.1045, 0.1309 Mev were observed, in agreement with earlier work. Weak conversion-electron lines attributed to gamma rays of energy 0.0187 and 0.1368 Mev were also observed.

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XXVI.The absorption band spectrum of selenium

Cited by 12 publications

References 5 publications

Absolute Rate Constants for the Reactions of Sulfur (³P_J) Atoms in Solution

Absolute Rate Constants for the Reactions of Sulfur (³P_J) Atoms in Solution

Dissociative excitation of selenium atoms in collisions of electrons with Se2 molecules

Radioactivity ofSm153andEu155

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XXVI.The absorption band spectrum of selenium

Cited by 12 publications

References 5 publications

Absolute Rate Constants for the Reactions of Sulfur (3PJ) Atoms in Solution

Absolute Rate Constants for the Reactions of Sulfur (3PJ) Atoms in Solution

Dissociative excitation of selenium atoms in collisions of electrons with Se2 molecules

Radioactivity ofSm153andEu155

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Product

Resources

About

Absolute Rate Constants for the Reactions of Sulfur (³P_J) Atoms in Solution

Absolute Rate Constants for the Reactions of Sulfur (³P_J) Atoms in Solution