Alexander Herlert

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For accurate mass measurements and identification of atomic and molecular species precise mass calibration is mandatory. Recent studies with laser desorption/ionization and time-of-flight analysis of cluster ion production by use of fullerene and gold targets demonstrate the generation of atomic clusters for calibration purposes. Atomic ion results from the(More)
Formation and stability patterns of silver dianionic and gold trianionic clusters are investigated with Penning-trap experiments and a shell-correction method including shape deformations. The theoretical predictions pertaining to the appearance sizes and electronic shell effects are in remarkable agreement with the experiments. Decay of the multiply(More)
The masses of the neutron-rich radon isotopes {223-229}Rn have been determined for the first time, using the ISOLTRAP setup at CERN ISOLDE. In addition, this experiment marks the first discovery of a new nuclide, 229Rn, by Penning-trap mass measurement. The new, high-accuracy data allow a fine examination of the mass surface, via the valence-nucleon(More)
Ramsey's method of separated oscillatory fields is applied to the excitation of the cyclotron motion of short-lived ions in a Penning trap to improve the precision of their measured mass values. The theoretical description of the extracted ion-cyclotron-resonance line shape is derived and its correctness demonstrated experimentally by measuring the mass of(More)
High-precision mass measurements on neutron-rich zinc isotopes (71m,72-81)Zn have been performed with the Penning trap mass spectrometer ISOLTRAP. For the first time, the mass of 81Zn has been experimentally determined. This makes 80Zn the first of the few major waiting points along the path of the astrophysical rapid neutron-capture process where(More)
Azimuthal quadrupolar excitation is a commonly used technique in the field of ion cyclotron resonance mass spectrometry, in particular in combination with buffer-gas collisions to achieve axialization of the stored ions. If the quadrupolar excitation is applied with only one phase to a set of two opposing ring segments (rather than the "regular" method(More)
Clusters consisting of a few atoms build the bridge between individual atoms and the condensed phase of matter and they are, thus, of high general interest. Over the last two decades, considerable progress has been made in the study of their properties, and ion storage techniques, in particular the use of ion cyclotron resonance (Penning) traps, are(More)
A. Herlert†1, S. Baruah2, D. Beck3, K. Blaum3,4, M. Breitenfeldt2, P. Delahaye1, M. Dworschak4, S. George3,4, C. Guénaut5, U. Hager6, F. Herfurth3, A. Kellerbauer7, H.-J. Kluge4,8, D. Lunney9, D. Neidherr4, R. Savreux3, S. Schwarz5, L. Schweikhard2, and C. Yazidjian3 1CERN, Geneva, Switzerland; 2Ernst-Moritz-Arndt-Universität, Greifswald, Germany; 3GSI,(More)
Mass measurements of (96,97)Kr using the ISOLTRAP Penning-trap spectrometer at CERN-ISOLDE are reported, extending the mass surface beyond N=60 for Z=36. These new results show behavior in sharp contrast to the heavier neighbors where a sudden and intense deformation is present. We interpret this as the establishment of a nuclear quantum phase transition(More)