The Diels–Alder addition reactions of a series of acenes (anthracene, 9,10-dimenthylanthracene, tetracene and pentacene) to C60 fullerene are next to equilibrium reactions and were analyzed using a classic chemical thermodynamics approach using group increment calculations. In the case of the C60/anthracene adducts and C60/dimethylanthracene

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One of the biggest challenges in heliophysics is to decipher the magnetic structure of the solar chromosphere. The importance of measuring the chromospheric magnetic field is due to both the key role the chromosphere plays in energizing and structuring the outer solar atmosphere and the inability of extrapolation of photospheric fields to

The characteristics of the chromospheres of late-type dwarf stars were studied using the CoudeEchelle Spectrograph (CES) at ESO and the IUE. The study focused on the h and k Mg II lines of F and G dwarfs. The stability of the IUE spectra permitted calculations of averaged absorption features and the subtraction of the Mg II lines to leave intrinsic

The K1V late-type dwarf α Cen B has been monitored to search for spectroscopic variability in the Ca II H chromospheric line during its rotational period. The observations were made with the Coudé Echelle Spectrograph with the 1.4 Coudé Auxiliary Telescope at ESO, with spectral resolution 80000. Variability in flux up to 29 % and profile

We present subarcsecond-resolution, ground-based, near-infrared images of the central regions of a sample of 12 barred galaxies with circumnuclear star formation activity, which is organized in ring-like regions typically 1kpc in diameter. We also present Hubble Space Telescope near-infrared images of 10 of our sample galaxies, and compare them