Observing 13C-13C connectivities at high magnetic fields and very high spinning frequencies

We report the application of a dipolar recoupling sequence for the observation of (13)C-(13)C connectivities in biomolecules at high magnetic fields (B(0)≥ 21.1 T) and ultra-high magic angle spinning frequencies (ν(R) = 60 kHz). The efficiency and the robustness of this double-quantum technique are demonstrated on the YajG protein (19.6 kDa).     

Experimental transition probability for theE1 intercombination transition in Be-like Xe50+

The 2s^{2 1}S₀ — 2s2p³P°₁ intercombination transition in Be-like Xe⁵⁰⁺ has been observed and the intensity decay with time has been measured using a foil-excited fast ion beam. The transition wavelength value is found to be λ = (9.81±0.05) nm and the upper level lifetime to be τ = (0.47±0.05) ns. Both values agree with recent theoretical predictions.     

Theory of spectral hole burning for the study of ultrafast electron dynamics in metal nanoparticles

In order to study the ultrafast relaxation dynamics of surface plasmon excitation in metal nanoparticles in the presence of inhomogeneous line broadening and investigate the influence of the reduced dimensions on the dephasing time T₂ in the size regime below about 10 nm, we have recently demonstrated a novel technique based on persistent spectral hole burning [1]. Here, we describe a theoretical model that has been developed for evaluation of the experimental data and precise determination of T₂ for particles of different size and shape. Comparison of the model to experimental data for Ag nanoparticles on sapphire shows that the theoretical treatment does not only reproduce the shape of the generated holes but also the dependence of their widths on the applied laser fluence. As a result, we have a reliable and versatile tool at hand making possible systematic studies of the ultrafast electron dynamics in small metal particles, and the dependence of the femtosecond dephasing time on their size, shape and surrounding dielectric. Received: 12 September 2001 / Published online: 15 October 2001     

Magnetic-dipole hyperfine structure in 4d- and 5d-shell atoms

The magnetic-dipole hyperfine interaction constantsA of low-lying metastable atomic levels in⁹¹Zr,¹⁸¹Ta,¹⁸³W, and¹⁹¹Ir determined from atomic-beam magnetic-resonance investigations are analyzed with respect to the effective-operator formalism. Similar results for other 4d- and 5d-shell atoms are also tabulated. The experimental results for the effective 〈r ^?3〉 values are compared with relativistic predictions for the 4d ^N 5s and 5d ^N 6s ² series.     

Hyperfine structure of the 4s4p1P1-state of67Zn by level crossing spectroscopy

The magnetic dipole coupling constantA of the 4s 4p¹P₁ state of⁶⁷Zn was measured in a level crossing experiment. The result is A(4s4p¹P₁ ⁶⁷Zn)= 17.7(5) MHz. In a modified Breit-Wills theory thisA factor leads to a parameter λ_P= 0.71(3), which describes the difference in the radial wave functions of thep-electron in 4s4p¹P₁ and³P₁ states respectively. The lifetime of the 4s4p¹P₁ state was remeasured by Hanle-effect experiments. The result τ=1.41± 0.04 nsec is in good agreement with other measurements.