The generation of magic number silica clusters [(SiO 2 ) n O 2 H 3 ]with n ) 4 and 8 by XeCl laser (308 nm) ablation of porous siliceous materials is reported. The production of magic cluster [(SiO 2 ) 4 O 2 H 3 ]can be enhanced by sample selection and experimental optimization so that it becomes the most prominent species in silica clusters. To study the structure of the magic cluster [(SiO 2 ) 4 O 2 H 3 ] -, we performed structural optimization for the neutral bare cluster (SiO 2 ) 4 , the neutral complex cluster (SiO 2 ) 4 O 2 H 4 , and the anionic cluster [(SiO 2 ) 4 O 2 H 3 ]at the HF/6-31G** level. It was found that the ground state of the bare silica tetramer has a linear chain structure whereas a pseudotetrahedral cage-like structural isomer of S 4 symmetry is most stable for the complex cluster (SiO 2 ) 4 O 2 H 4 . The stabilization of the three-dimensional (3D) structure can be attributed to the active participation of the O 2 H 4 group in chemical bonding during cluster formation. Our theoretical calculation and bonding analysis indicate that the magic number anionic cluster [(SiO 2 ) 4 O 2 H 3 ]might also take a pseudotetrahedral structure similar to (but with a different symmetry) that of the neutral precursor (SiO 2 ) 4 O 2 H 4 as the ground state in which the valence, coordination, and bonding characteristics of all the constituent atoms are nearly fully satisfied.

Contrasting behaviors of Rh with Y(La) in the formation of metallofullerenes by excimer laser ablation of metal fullerides C60Rh x and C60M x (M = La, Y) were observed. For Rh, two sequences of rhodium metallofullerenes, C2 n Rh and C2 n +1Rh with even and odd numbers of carbon atoms, are formed in both the negative and positive ion channels, but for La and Y, only the metallofullerene sequence with even numbers of carbon atoms is formed and only in the positive ion channel. Evidence of the encapsulation of La and Y atoms in fullerene cages forming endohedral fullerenes has been observed, whereas the Rh atom is most probably incorporated into the network of the fullerene cage or pseudo-fullerene forming substitutional metallofullerenes. Density functional theory calculation was performed to determine the structures of the model metallofullerenes C53Rh and C54M (M = Rh and Y). The calculated results are in general consistent with the experimental observations.

This report presents the preparation and characterization of H2OOO+, an important intermediate in water-oxygen chemistry. The H2OOO+ cation was produced by co-deposition of H2O/Ar with radio frequency discharged O2/Ar at 4 K and was identified by four fundamental infrared absorptions. Quantum chemical calculations indicate a doublet ground state with a H2O-O2 hemi-bonded Cs structure.

When a high-frequency discharged CS 2 :O 2 :Ar sample was condensed at 4 K, new absorptions at 1003.1 and 567.7 cm -1 were produced. Isotopic substitution ( 13 CS 2 /O 2 , C 34 S 2 /O 2 , CS 2 / 18 O 2 , and mixtures) shows that these new absorptions are due to S-O and S-S stretching vibrations, which involve two inequivalent S atoms and one O atom. The photosensitive behavior and the agreement with frequencies and isotopic frequency ratios from quantum chemical calculations substantiate assignment of these absorptions to the SSOanion, which was predicted to have a bent structure with elongated S-S and S-O bond lengths relative to those of S 2 O.