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Abstract: Photoelectron–Auger electron coincidence spectroscopy probes the dicationic states produced by Auger decay following the photoionization of core or inner valence levels in atoms, molecules or clusters. Moreover, the technique provides valuable insight into the dynamics of core hole decay. This paper serves the dual purpose of demonstrating the additional information obtained by this technique compared to Auger spectroscopy alone as well as of describing the new IPP/FHI apparatus at the BESSY II synchrotron radiation source. The distinguishing feature of the latter is the capability to record both the photoelectron and Auger electron with good energy and angle resolution, for which purpose a large hemispherical electrostatic analyser is combined with several linear time-of-flight spectrometers. New results are reported for the K-shell photoionization of oxygen (O2) and the subsequent KVV Auger decay. Calculations in the literature for non-coincident O2 Auger spectra are found to be in moderately good agreement with the new data. [Copyright &y& Elsevier]

The inner-shell C 1s photoionization of randomly oriented molecules of the chiral compound carvone has been investigated using circularly polarized synchrotron radiation up to 30 eV above threshold. Binding energies of the C_==O and C_H2== carbon 1s orbitals were determined to be 292.8±0.2 and 289.8±0.2 eV, respectively. The remaining C_–H C 1s levels substantially overlap under an intense central peak centered at 290.5±0.2 eV. The angle-resolved photoemission from the carbonyl carbon C_==O core orbital in pure carvone enantiomers shows a pronounced circular dichroism of ∼6% at the magic angle of 54.7° to the light beam propagation direction. This corresponds to an expected 0°–180° forward-backward electron emission asymmetry of ∼10%. On changing between the R and S enantiomers of carvone the sense or sign of the asymmetry and associated dichroism effectively reverses. The observed circular dichroism, and its energy dependence, is well accounted for by calculations performed in the pure electric dipole approximation. [ABSTRACT FROM AUTHOR]

Guidance from the Institute for Quality and Efficiency in Health Care (IQWiG) on cost estimation in cost–benefit assessments in Germany acknowledges the need for standardization of costing methodology. The objective of this review was to assess current methods for deriving clinical event costs in German economic evaluations. A systematic literature search of 24 databases (including MEDLINE, BIOSIS, the Cochrane Library and Embase) identified articles, published between January 2005 and October 2009, which reported cost-effectiveness or cost-utility analyses. Studies assessed German patients and evaluated at least one of 11 predefined clinical events relevant to patients with diabetes mellitus. A total of 21 articles, describing 199 clinical cost events, met the inclusion criteria. Year of costing and time horizon were available for 194 (97%) and 163 (82%) cost events, respectively. Cost components were rarely specified (32 [16%]). Costs were generally based on a single literature source (140 [70%]); where multiple sources were cited (32 [16%]), data synthesis methodology was not reported. Cost ranges for common events, assessed using a Markov model with a cycle length of 12 months, were: acute myocardial infarction (nine studies), first year, 4,618–17,556 €; follow-up years, 1,006–3,647 €; and stroke (10 studies), first year; 10,149–24,936 €; follow-up years, 676–7,337 €. These results demonstrate that costs for individual clinical events vary substantially in German health economic evaluations, and that there is a lack of transparency and consistency in the methods used to derive them. The validity and comparability of economic evaluations would be improved by guidance on standardizing costing methodology for individual clinical events. [ABSTRACT FROM AUTHOR]

Abstract: Using photoemission we have investigated free argon clusters from a supersonic nozzle expansion in the photon energy range from threshold up to 28eV. Measurements were performed both at high resolution with a hemispherical electrostatic energy analyser and at lower resolution with a magnetic bottle device. The latter experiments were performed for various mean cluster sizes. In addition to the ≈1.5eV broad 3p-derived valence band seen in previous work, there is a sharper feature at ≈15eV binding energy. Surprisingly for non-oriented clusters, this peak shifts smoothly in binding energy over the narrow photon energy range 15.5–17.7eV, indicating energy band dispersion. The onset of this bulk band-like behaviour could be determined from the cluster size dependence. [Copyright &y& Elsevier]

Low-energy electrons are the most abundant product of ionizing radiation in condensed matter. The origin of these electrons is most commonly understood to be secondary electrons ionized from core or valence levels by incident radiation and slowed by multiple inelastic scattering events. Here, we investigate the production of low-energy electrons in amorphous medium-sized water clusters, which simulate water molecules in an aqueous environment. We identify a hitherto unrecognized extra source of low-energy electrons produced by a non-local autoionization process called intermolecular coulombic decay (ICD). The unequivocal signature of this process is observed in coincidence measurements of low-energy electrons and photoelectrons generated from inner-valence states with vacuum-ultraviolet light. As ICD is expected to take place universally in weakly bound aggregates containing light atoms between carbon and neon in the periodic table, these results could have implications for our understanding of ionization damage in living tissues. [ABSTRACT FROM AUTHOR]