Theory of attosecond absorption spectroscopy in krypton

A theory for time-domain attosecond pump–attosecond probe photoabsorption spectroscopy is formulated and related to the atomic response. The theory is illustrated through a study of attosecond absorption spectroscopy in krypton. The atomic parameters entering the formulation such as energies and Auger widths, as well as wave functions and dipole coupling matrix elements, are determined by accurate many-body structure calculations. We create a hole in a valence shell by an attosecond pump, couple an inner-shell electron to the hole by an attosecond probe, and then monitor the formation of the hole in this manner. In a second example, a hole is created in an inner shell by the first pulse, and the second probe pulse couples an even more tightly bound state to that hole. The hole decays in this example by Auger electron emission, and the absorption spectroscopy follows the decay of the hole and the associated coherences in real time.

Characterisation of recently emerged multiple antibiotic-resistant Salmonella enterica serovar typhimurium DT104 and other multiresistant phage types from Danish pig herds

A total of 670 isolates of Salmonella enterica were isolated from Danish pig herds, phage typed and tested for susceptibility to amoxycillin + clavulanate, ampicillin, colistin, enrofloxacin, gentamicin, neomycin, spectinomycin, streptomycin, tetracyclines, and trimethoprim + sulphadiazine. S enterica serovar typhimurium (S typhimurium) isolates resistant to ampicillin, streptomycin and tetracycline and three isolates of S typhimurium DT104, two from 1994 and one from 1995, were further tested for resistance against chloramphenicol and sulphonamide and analysed by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme Xba I, Overall, 66 per cent of the 670 isolates were sensitive to all the antimicrobial agents tested. Eleven isolates of S typhimurium were resistant to ampicillin, streptomycin and tetracycline and also resistant to other antibiotics in different resistance patterns. Seven different multiresistant clones were identified, The most common clones were four isolates of DT104 and three isolates of DT193, TWO Of the three S typhimurium DT104 from 1994 and 1995 were sensitive to all the antimicrobials tested whereas the remaining isolate from 1994 was resistant to spectinomycin, streptomycin and sulphonamides. All three isolates showed PFGE profiles identical to the four multiresistant DT104 isolates. Compared with most other countries antimicrobial resistance among S enterica isolated from Danish pig herds is uncommon, However, several different multiresistant clones were found

Attosecond electron interferometry

Attosecond extreme ultraviolet light pulses have the potential to resolve the ultrafast electron dynamics that govern basic properties of atoms, molecules, and solids. Here we present three different interferometric pump-probe methods aiming to access not only the temporal dynamics, but also state specific phase information after excitation/ionization using attosecond pulses

Attosecond Time-Resolved Photoemission Spectroscopy in Condensed Matter – Photoelectron Wave Phase Shifts and Time Delays

Heinzmann U. Attosecond Time-Resolved Photoemission Spectroscopy in Condensed Matter – Photoelectron Wave Phase Shifts and Time Delays. In: Plaja L, Torres R, Zaïr A, eds. Attosecond Physics. Optical Sciences. Vol 177. Berlin, Heidelberg: Springer; 2013: 231-253.The chapter reviews the first attosecond time-resolved photoemission experiment performed on a tungsten single crystal surface and discusses the status and the limitations of this research field in condensed matter. It also discusses the relationship between photoelectron wave phase shifts obtained in spin-resolved photoemission experiments and attosecond Wigner time delays of the photoelectron emission for certain orbital angular momenta. Finally it reviews similar ESCA (electron spectroscopy for chemical analysis) photoemission measurements recently performed on a solid as well as on a molecular adsorbate with some femtosecond time and 0.1 eV energy resolution