ZIB

1

Digitale Medien

Resonance ionization mass spectroscopy for trace analysis of neptunium (1993)

Riegel, J. ; Deißenberger, R. ; Herrmann, G. ; [weitere]

Springer

Applied physics 56 (1993), S. 275-280

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ISSN: 1432-0649

Schlagwort(e): 32.30.—r ; 32.80.Rm ; 32.80.Dz ; 35.10.Hn

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract Resonance ionization mass spectroscopic (RIMS) measurements for trace analysis and spectroscopy of 237Np, the ecologically most important isotope of neptunium, are described. The chemical procedure for the separation of neptunium from aqueous samples as well as the preparation of filaments for RIMS are outlined. Several two- and three-step excitation schemes have been investigated in order to find suitable conditions for the sensitive detection of 237Np. Using a three-step, three-color excitation and ionization scheme an overall detection efficiency of 3×10−8 was obtained, resulting in a detection limit of 4×108 atoms (160 fg) of 237Np. The hyperfine structure splittings of the levels under investigation, which influence the detection limit, were measured. A new method to determine the first ionization potential (IP) was applied to neptunium yielding a value of IP=6.2655(2) eV.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00325216

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2

Digitale Medien

Resonance lonization mass spectroscopy with a pulsed thermal atomic beam (1987)

Krönert, U. ; Becker, St. ; Hilberath, Th. ; [weitere]

Springer

Applied physics 44 (1987), S. 339-345

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ISSN: 1432-0630

Schlagwort(e): 07.65.Eh ; 32.70.Fw ; 32.80.Dz

Quelle: Springer Online Journal Archives 1860-2000

Thema: Maschinenbau , Physik

Notizen: Abstract Resonance ionization mass spectroscopy (RIMS) and pulsed-laser induced desorption (PLID) have been combined for ultrasensitive detection and spectroscopy of very small samples of refractive elements. The method has been tested and applied to laser spectroscopy of 5×109 atoms (1.5 pg) of195Au (T 1/2= 183d) implanted at the ISOLDE online mass separator with 60 keV into graphite. A pulsed thermal atomic beam was formed by laser desorption with a 10 ns Nd∶Yag laser pulse. Subsequently the atoms were photoionized in a three-colour, three-step resonant excitation to an autoionizing state. The selectivity was enhanced by a time-of-flight measurement of the photo ions. In resonance, one ion was detected per 105 atoms implanted resulting in a gain in detection efficiency by three orders of magnitude in comparison to the use of a continuous atomic beam. In the course of the experiments several unknown autoionizing states were found, and the lifetime of the 6d 2 D 3/2 state of gold was determined to beτ=10.7(6) ns.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00624601

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3

Digitale Medien

Lifetime measurements of highly excited Rydberg states of strontium I (1993)

Kunze, S. ; Hohmann, R. ; Kluge, H. -J. ; [weitere]

Springer

The European physical journal 27 (1993), S. 111-114

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ISSN: 1434-6079

Schlagwort(e): 32.70.Fw ; 32.80.Rm

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract Lifetimes of Rydberg states of the triplet-series 5s ns 3 S 1 withn = 19–23, 35 and 5s nd 3 D 3 withn = 18–20, 23–28 in the spectrum of neutral strontium have been determined. Observation of the exponential decay after excitation by a pulsed laser in a fast atomic beam and subsequent state-selective field ionization was employed. The lifetimes of the states of the3 S 1-series show the expectedn*3 dependence on the effective principal quantum number, while the3 D 3-series is disturbed by configuration mixing. Furthermore, state re-populations induced by black-body radiation have been observed.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01426757

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4

Digitale Medien

Fragmentation of gold clusters stored in a penning trap (1994)

Becker, St. ; Dietrich, G. ; Hasse, H.-U. ; [weitere]

New York, NY : Wiley-Blackwell

Rapid Communications in Mass Spectrometry 8 (1994), S. 401-402

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ISSN: 0951-4198

Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Physik

Notizen: The collision-induced dissociation of positively charged gold clusters (2-23 atoms) stored in a Penning trap has been studied. After collisions with rare gases, excited clusters predominantly decay by emission of one or two atoms. The loss of two atoms occurs most probably through the emission of a dimer rather than by a sequential evaporation. The minimum kinetic energies of clusters required to induce dissociation exhibit a pronounced odd-even effect. Clusters with an even number of delocalized electrons are more stable than those with an odd number.

Zusätzliches Material: 2 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/rcm.1290080512

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5

Digitale Medien

γgaucheEffects in the 1H and 13C NMR spectra of steroids. IIFor Part I, see Ref. 1. (1991)

Hammann, P. E. ; Kluge, H. ; Habermehl, G. G.

Chichester : Wiley-Blackwell

Organic Magnetic Resonance 29 (1991), S. 133-136

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ISSN: 0749-1581

Schlagwort(e): 17β-Substituted 14α-steroids ; 7α-substituted 14α-steroids ; 1H NMR ; 13C NMR ; Chemistry ; Analytical Chemistry and Spectroscopy

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: γgaucheEffects of 17β- and 7α-substituted 14α-steroids were studied by 1H and 13C NMR spectroscopy. A linear correlation was found between the 1H chemical shift of H-12β and the 13C chemical shift of C-12 for C-17β-substituted steroids and between the chemical shifts of H-14α and C-14 in C-7α-substituted compounds.

Zusätzliches Material: 2 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/mrc.1260290207

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6

Digitale Medien

γgauche effects in the 1H and 13C NMR spectra of steroids (1988)

Hammann, P. E. ; Habermehl, G. G. ; Kluge, H.

Chichester : Wiley-Blackwell

Organic Magnetic Resonance 26 (1988), S. 85-88

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ISSN: 0749-1581

Schlagwort(e): 13C NMR ; 1H NMR ; 12-Substituted-14β-hydroxy steroids ; 14α-Steroids ; Chemistry ; Analytical Chemistry and Spectroscopy

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: γgauche effects of 12-substituted-14β-hydroxy- and 14α-steroids were studied by 1H and 13C NMR spectroscopy. A linear correlation was found between the 1H chemical shift of 4H-17 and the 13C shift of C-17 for C-12-substituted steroids. This correlation can be explained by steric interactions.

Zusätzliches Material: 4 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/mrc.1260260118

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