Related papers: It Remains a Cage: Ionization Tolerance of C60 Ful…
We present a study of 16 PNe where fullerenes have been detected in their Spitzer spectra. This large sample of objects offers an unique opportunity to test conditions of fullerene formation and survival under different metallicity…
We report a computational study of the stability and infrared (IR) vibrational spectra of neutral and singly ionised fullerene cages containing between 44 and 70 carbon atoms. The stability is characterised in terms of the standard enthalpy…
The C_{60} molecule exhibits a remarkable stability and inertness that leads to its survival in ancient carbonaceous rocks initially subject to the high temperatures requisite for its formation. Elementary particles having very high…
Detections of C60 and C70 fullerenes in planetary nebulae (PNe) of the Magellanic Clouds and of our own Galaxy have raised the idea that other forms of carbon such as hydrogenated fullerenes (fulleranes like C60H36 and C60H18), buckyonions,…
[Abridged] Fullerenes have been recently detected in various circumstellar and interstellar environments, raising the question of their formation pathway. It has been proposed that they can form by the photo-chemical processing of large…
This paper is the third in a series reporting on a study of carbon abundances in a carefully chosen sample of planetary nebulae representing a large range in progenitor mass and metallicity. We make use of the IUE Final Archive database…
Planetary nebulae (and in general any photoionized region) can be classified as ionization-bounded or density-bounded. It is important to determine in which case is the planetary nebula studied to be able to estimate from nebular…
This paper is the fourth and final report on a project designed to study carbon abundances in a sample of planetary nebulae representing a broad range in progenitor mass and metallicity. We present newly acquired optical spectrophotometric…
When the neutral interstellar medium is exposed to EUV and soft X ray radiation, the argon atoms in it are far more susceptible to being ionized than the hydrogen atoms. We make use of this fact to determine the level of ionization in the…
We have observed that C$_{60}^+$ ions isolated in cryogenic matrixes show pronounced near-IR photoluminescence upon excitation in the near-IR range. By contrast UV photoexcitation does not lead to measurable luminescence. After the recent…
Interstellar molecules are thought to build up in the shielded environment of molecular clouds or in the envelope of evolved stars. This follows many sequential reaction steps of atoms and simple molecules in the gas phase and/or on (icy)…
The physical properties of the faint and extremely tenuous plasma in the far outskirts of galaxy clusters, the circumgalactic media of normal galaxies, and filaments of the cosmic web, remain one of the biggest unknowns in our story of…
We use the recent detection of He II absorption at $z=2.2-2.6$ in the line of sight of the quasar HS1700+64 to put bounds on the sources of ionization. We find that given the uncertainty in $\tauhgp$ and the model of absorption in the…
Small cationic fullerene fragments, produced by electron impact ionization of C60, were mass-selected and accumulated in cryogenic Ne matrixes. Optical absorption spectroscopy of these fragments with up to 18 carbon atoms revealed linear…
We recently identified several emission bands in the Spitzer-IRS spectrum of the unusual planetary nebula Tc 1 with the infrared active vibrational modes of the neutral fullerene species C60 and C70. Since then, the fullerene bands have…
The ionizing continuum shape of quasars is generally not directly observable, but indirect arguments, based on photoionization models and thin accretion disk models suggest that it should peak in the extreme UV, and drop steeply into the…
The presence of neutral C60 fullerenes in circumstellar environments has been firmly established by astronomical observations as well as laboratory experiments and quantum-chemistry calculations. However, the large variations observed in…
Our previous studies [J. Phys. B 53, 125101 (2020); Euro. Phys. J. D 74, 191 (2020)] have predicted that the atom-fullerene hybrid photoionization properties for X = Cl, Br and I endohedrally confined in C60 are different before and after…
Fullerenes are a particularly stable class of carbon molecules in the shape of a hollow sphere or ellipsoid that might be formed in the outflows of carbon stars. Once injected into the interstellar medium (ISM), these stable species survive…
The dissociation and subsequent ionisation of molecular material in a detached, spherically symmetric stellar wind is modelled as a star evolves from the post-asymptotic giant branch phase to a planetary nebula (i.e. from a stellar…