Solid C58 films

Abstract

A new solid material has been created in ultra high vacuum by utilizing the aggregation process of C58 molecules deposited onto highly oriented pyrolytic graphite from a mass selected low-energy ion beam comprising C58+. Cluster fluxes of up to 3x10(11) ions s-1 cm-2 with impinging kinetic energies of 6+/-0.5 eV were typically applied. Growth of the solid C58 phase proceeds according to the cluster-aggregation-based Volmer-Weber scenario where initially ramified 2D islands transform into 3D pyramid-like structures at higher coverages. The C58 films created exhibit much higher thermal stability than the C60 solid phase. Sublimation of C58 sets in at a temperature of 700 K. Ultraviolet photoionization spectra (He I, 21.2 eV) yield a molecular ionization potential in the range between 6.6 and 7 eV. Density functional and Hartree-Fock theories suggest that the formation of C58 dimers and higher multimers upon deposition/aggregation gives rise to the high thermal stability and unique electronic properties of this material.

Fragmentation pathways of nanofractal structures on surfaces

“…11,14,15,21,[23][24][25][26][27] The formation of such systems provides a natural framework for studying disordered structures on a surface because fractals are generally observed in the far-from-equilibrium growth regime. For example, fractals consisting of Ag, 14,15,21 Au, 28 Fe-N clusters, 26 and C 60 molecules 29,30 have been fabricated on different surfaces with the use of the cluster deposition technique. 1,2 The growth process of fractals has been extensively studied in experiments.…”

C n films (n=50, 52, 54, 56, and 58) on graphite: Cage size dependent electronic properties

“…15,16 Thermal desorption spectroscopy ͑TDS͒, ultraviolet photoelectron spectroscopy ͑UPS͒, and atomic force microscopy ͑AFM͒ were used to study deposition dynamics and the electronic/ a͒ Author to whom correspondence should be addressed. 15,16 Thermal desorption spectroscopy ͑TDS͒, ultraviolet photoelectron spectroscopy ͑UPS͒, and atomic force microscopy ͑AFM͒ were used to study deposition dynamics and the electronic/ a͒ Author to whom correspondence should be addressed.…”

“…15,16 In addition to the parent and primary fragment ions, smaller fragments C n + ͑n = 50, 52, 54, and 56͒ can be produced in sufficient intensities to also allow the fabrication of multilayer films by soft landing. 15,16 In addition to the parent and primary fragment ions, smaller fragments C n + ͑n = 50, 52, 54, and 56͒ can be produced in sufficient intensities to also allow the fabrication of multilayer films by soft landing.…”

Dimerization of Defect Fullerenes and the Orientational Phase Transition in Oxidized C<SUB>60</SUB> Fullerite

“…Such sp 3 -hybridization was observed before when studying 58 the mechanism of C 2 abstraction from C 60 , while simulating 59 the polymerization of C 60 , in C 58 fullerene tetramers, 60 and in C n -C n fullerene dimers (n = 50-60). 56 In the latter case, the largest binding energy belongs to the dimer with n = 50.…”

“…The Raman spectra of a (O 2 x C 60 sample shown in Figure 1 contains all 10 peaks (2A g + 8H g corresponding to Raman active modes in buckyball C 60 The C 60 fullerite doping with alkali metals results into a softer tangential mode A g (2) that renders a convenient tool [15][16][17] for estimating the amount of metal x in M x C 60 samples since the mode shift depends linearly on x and equals ∼6 cm −1 per an atom M. Since our value of 1467.2 cm −1 is smaller than the value of 1468.4 in the undoped fullerite, one may conclude that there is a small charge transfer (∼0.2e) from oxygen, which is in agreement with the results of Gu et al 18 A small intensity peak at 1538 cm −1 can be assigned to oxygen (see the insert in Fig. 1) since there is no such peak in (Ar) x C 60 samples obtained under similar conditions.…”