We have produced a catalog of 378 Galactic O stars with accurate spectral classifications that is complete for V < 8 but includes many fainter stars. The catalog provides cross-identifications with other sources; coordinates (obtained in most cases from Tycho-2 data); astrometric distances for 24 of the nearest stars; optical (Tycho-2, Johnson, and Strömgren) and NIR photometry; group membership, runaway character, and multiplicity information; and a Web-based version with links to on-line services.

The gas-phase infrared spectra of radical cationic and protonated corannulene were recorded by infrared multiple-photon dissociation (IRMPD) spectroscopy using the IR free electron laser for infrared experiments. Electrospray ionization was used to generate protonated corannulene and an IRMPD spectrum was recorded in a Fourier-transform ion cyclotron resonance mass spectrometer monitoring H-loss as a function of IR frequency. The radical cation was produced by 193-nm UV photoionization of the vapor of corannulene in a 3D quadrupole trap and IR irradiation produces H, H 2 , and C 2 H x losses. Summing the spectral response of the three fragmentation channels yields the IRMPD spectrum of the radical cation. The spectra were analyzed with the aid of quantum-chemical calculations carried out at various levels of theory. The good agreement of theoretical and experimental spectra for protonated corannulene indicates that protonation occurs on one of the peripheral C-atoms, forming an sp 3 hybridized carbon. The spectrum of the radical cation was examined taking into account distortions of the C 5v geometry induced by the Jahn-Teller effect as a consequence of the degenerate 2 E 1 ground electronic state. As indicated by the calculations, the five equivalent C s minima are separated by marginal barriers, giving rise to a dynamically distorted system. Although in general the character of the various computed vibrational bands appears to be in order, only a qualitative match to the experimental spectrum is found. Along with a general redshift of the calculated frequencies, the IR intensities of modes in the 1000-1250 cm −1 region show the largest discrepancy with the harmonic predictions. In addition to CH "in-plane" bending vibrations, these modes also exhibit substantial deformation of the pentagonal inner ring, which may relate directly to the vibronic interaction in the radical cation.

Gas-phase infrared spectra of several ionized nitrogen substituted polycyclic aromatic hydrocarbons (PANHs) have been recorded in the 600-1600 cm −1 region via IR multiple-photon dissociation (IRMPD) spectroscopy. The UV photoionized PANH ions are trapped and isolated in a quadrupole ion trap where they are irradiated with an IR free electron laser. The PANHs were studied in their radical cation (PANH + ) and protonated (H + PANH) forms, and include quinoline, isoquinoline, phenanthridine, benzo[h]quinoline, acridine, and dibenzo[f,h]quinoline. Experimental IRMPD spectra were interpreted with the aid of density functional theory methods. The PANH + IR spectra are found to resemble those of their respective non-nitrogenated PAH cations. The IR spectra of H + PANHs are significantly different owing to the NH inplane bending vibration, which generally couples very well with the aromatic CH bending and CC stretching modes. Implications of the NPAH (+, H + ) laboratory spectra are discussed for the astrophysical IR emissions and, in particular, for the band at 6.2 μm.

In fullerenization chemistry, the whittling of carbon units from graphenic all-hexagon systems drives the local structural transformation from a sp 2 -hybridized composition into a pyramidal-like carbon composition. This chemical process recently observed in real time is believed to involve the self-sculpting action of local strain forces leading to fullerene growth. Here, an atomistic structural representation of this process is elaborated and correlated with spectral simulations of graphenic molecular models in varied curvaturestrain stages that allows uncovering the fingerprint of fullerenization. Application of this fingerprint to Infrared Space Observatory data reveals that interstellar graphenic matter undergoes fullerenization, leading to the formation of strained fullerene-like 3D species. This suggests an evolutionary chemical interrelation between forms of strained molecular nanostructures, and includes bowls, cones and cages. These results offer a valuable platform in all-carbon chemistry useful to advance our understanding of both experimental and interstellar sp 2 -carbon nanostructures.

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