Formation of Doubly and Triply Charged Fullerene Dimers in Superfluid Helium Nanodroplets.

Sequential ionization of fullerene cluster ions (C_{60})_{n}^{+} within multiply charged helium nanodroplets leads to the intriguing phenomenon of forming and stabilizing doubly and triply charged fullerene oligomers. While the formation of doubly charged dimers (C_{60})_{2}^{2+} has been predicted in earlier studies, the observation of even triply charged ones (C_{60})_{2}^{3+} is highly surprising. This remarkable resilience against Coulomb explosion is achieved through efficient cooling within the superfluid environment of helium nanodroplets and a sequential ionization scheme that populates covalently bound or physisorbed fullerene dimers.

Spectroscopic investigation of size-dependent CO binding on cationic copper clusters: analysis of the CO asymmetric stretch.

Photofragmentation spectroscopy, combined with quantum chemical computations, was employed to investigate the position of the asymmetric CO stretch in cold, He-tagged Cu[CO] ( = 1-10) and Cu[CO][HO] ( = 1-7) complexes. A blue shift in the band position was observed compared to the free CO molecule for Cu[CO] complexes. Furthermore, this shift was found to exhibit a notable dependence on cluster size, progressively redshifting with increasing cluster size.

Size limits and fission channels of doubly charged noble gas clusters.

Small, highly charged liquid droplets are unstable with respect to spontaneous charge separation when their size drops below the Rayleigh limit or, in other words, their fissility parameter exceeds the value 1. The absence of small doubly charged atomic cluster ions in mass spectra below an element-specific appearance size has sometimes been attributed to the onset of barrierless fission at = 1. However, more realistic models suggest that marks the size below which the rate of fission surpasses that of competing dissociative channels, and the Rayleigh limit of doubly charged van der Waals clusters has remained unchartered.

Doubly charged dimers and trimers of heavy noble gases.

Many doubly charged heteronuclear dimers are metastable or even thermodynamically stable with respect to charge separation. Homonuclear dicationic dimers, however, are more difficult to form. He was the first noble gas dimer predicted to be metastable and, decades later, observed.

Mixed Cluster Ions of Magnesium and C.

Magnesium clusters exhibit a pronounced nonmetal-to-metal transition, and the neutral dimer is exceptionally weakly bound. In the present study, we formed pristine Mg ( = 1-100, = 1-3) clusters and mixed (C)Mg clusters ( = 1-7, = 1, 2) upon electron irradiation of neutral helium nanodroplets doped with magnesium or a combination of C and magnesium. The mass spectra obtained for pristine magnesium cluster ions exhibit anomalies, consistent with previous reports in the literature.