[en] We present density functional theory calculations of C₆₀^q- and C₇₀^q- (q=0-2) isomers that contain zero to three pairs of adjacent pentagons. The first- and second-electron affinities for the archetype structures of C₆₀ and C₇₀ are close to the experimental results, while isomers with pentagon adjacencies have significantly higher values. The results are rationalized in view of the numbers and locations of pentagon adjacencies in the fullerene cages and the spherical aromaticity for the magic number C₇₀^2- with a closed (l=5) electronic shell in the spherical gas model

[en] A large number of hydrogenated coronene, circumcoronene, and circumcircumcoronene isomers have been investigated by means of density functional theory calculations. The computation of their IR spectra puts forward significant differences between the different isomers in the 3 μm region and shows that hydrogenated polycyclic aromatic hydrocarbons can account for the aromatic infrared bands resulting from the absorption of light by the interstellar medium. In particular, the intense 3.3 μm band, as well as the weak features observed at 3.40, 3.46, 3.51, and 3.56 μm are reasonably reproduced by the present calculations. The latter two are only observed when hydrogenation takes place in tertiary carbon atoms, showing that the frequencies at which these IR bands appear are a consequence of their position and chemical environment within the molecule.

[en] The molecular fragmentation of doubly charged L-alanine in gas phase was studied in radiation synchrotron experiments. In this presentation, we summarize our theoretical study on the dynamics of this fragmentation, using various computational methods. We show that in practice the ground state MD simulations are able to statistically reproduce the experimental results of the photo-fragmentation initiated at the excited state. (paper)

[en] We present an implementation of the Microcanonical Metropolis Monte Carlo method based on statistical mechanics and electronic structure calculations. The method is designed to study any kind of fragmentation process. Here we show its capabilities to predict mass spectra of simple molecules. (paper)

[en] We present a combined experimental and theoretical study of the fragmentation of doubly-positively- charged amino acids in the gas phase. The combination of ab initio molecular dynamics simulations with ion- molecule collisions followed by multiple-coincidence mass spectrometric techniques, allows us to obtain a complete picture of the fragmentation dynamics. In addition to the expected Coulomb explosion, we have found evidence of hydrogen and hydroxyl-group migration processes, which leads to unusual fragmentation products. (paper)

[en] We report here on the molecular self-assembly of 7, 7′, 8, 8′ tetracyanoquinodimethane (TCNQ) (schematic representation of the molecule on figure 1(b)) on a single-crystal Cu(111) surface, followed by deposition of Fe and Mn, and on the formation of an ordered metal–organic coordination network of Fe (or Mn)–TCNQ units, which contains magnetic ions separated by 0.9 nm. (paper)

[en] Systematic molecular dynamics simulations based on the self-consistent charge density functional tight-binding method have been performed for the molecular collisions inside clusters of fullerene molecules, after prompt atom knockouts by the keV ions. The thermodynamic and kinetic stabilities, as well as the bonding features, have been investigated for the most stable dumbbell dimers C"+_1_8, C"+_1_9 and C"+_2_0. (paper)

[en] N-acetyl glycine and N-methyl glycine molecules in the gas phase are ionized by electron exchange with slow O"6"+ ions at an energy of 48 keV. After ionization, the methyl and acetyl substituted glycines dissociate into fragments analogous to that resulting from ionization and fragmentation of amino acids and peptides, respectively. N-acetylglycine which contains a peptide bond also effectively tautomerizes to the diol form. Such tautomerization is typical for amino acids, however, we show that the tautomerization mechanism of the N-acetylglycine is different. (paper)