Adsorption ofpara-hydrogen on fullerenes

Abstract

Adsorption of para-hydrogen on the outer surface of a single fullerene is studied theoretically, by means of ground state Quantum Monte Carlo simulations. We compute energetics and radial density profiles of para-hydrogen for various coverages on a variety of small fullerenes. The equilibrium adsorbed solid monolayer is commensurate with the surface of the fullerene; as the chemical potential is increased, a discontinuous change is generally observed, to an incommensurate, compressible layer. Quantum exchanges of hydrogen molecules are absent in these systems.

Solvation of carbonaceous molecules by para-H2 and ortho-D2 clusters. II. Fullerenes

“…However, some quantitative changes in the collective behavior above the commensurate covering size of 32 were noted, though not as dramatic as the defect-induced melting seen in helium-coated C + 60 at the same coverage. 36 The present results are also at variance with previous quantum Monte Carlo results by Turnbull and Boninsegni 40 who reported the first solvation shell to be complete with 40 para-H 2 molecules (in an incommensurate arrangement). The LJ potential used by these authors (LD parameters) to model the H 2 -carbon interaction 46 is similar to our own potential, hence the reason for this discrepancy could lie in the higher temperature of 2 K considered in the present investigation.…”

“…Recently, mass spectrometry experiments in the Scheier group have shed light onto the coating of hydrogen clusters on the cationic fullerenes C + 60 and C + 70 , for which strong drops in abundances at sizes 49 and 51, respectively, were interpreted as the manifestation of shell completion. 39 These experimental results are at variance with the only existing theoretical investigation that we are aware of, 40 which predicted that shell closure takes place much earlier, near 40 para-H 2 molecules for the neutral dopant C 60 .…”

“…It may thus well be that exchange effects, which were neglected here, contribute to reducing the shell occupancy as predicted by Turnbull and Boninsegni. 40 The incommensurate nature of the solvation shell, also found in the case of the helium solvent, originates mainly from the interplay between the competition between the H 2 -H 2 and H 2 -carbon interactions, but also from the corrugation of the fullerene surface which above 32 molecules hinders regular arrangements. The initially dominant H 2 -carbon interaction makes hydrogen molecules bind preferentially in contact with the fullerene and remain rather distant from each other.…”

The Use of Bilingual Methods through Scientific Approach at Integrated Subject to Improve the Student’s English Skills

“…The result of the previous study on bilingual methods can be several reasons why bilingual methods are important to apply in a lesson. As presented by Turnbull (2016) which concludes that bilingual model learning may be applied to train foreign language abilities of children other than the original language. But, in the learning process, bilingual methods become less effective if only done by the teacher, so it is also required the active participation of students.…”

H2 Adsorption in Metal‐Organic Frameworks: Dispersion or Electrostatic Interactions?

“…Therefore, systems designed for H 2 storage should be highly polarisable and have a large specific surface area with favourable pore sizes of~0.6 nm. [6][7][8] Graphitic (sp 2 ) carbon structures (graphene slit pores, [8] carbon nanotubes, [9] fullerenes [10] and more advanced materials (C 60 intercalated graphite, [11] honeycomb graphite [12,13] etc.)) belong to this group.…”