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

Abstract

Articles you may be interested in Solvation of carbonaceous molecules by para-H 2 and ortho-D 2 clusters. I. Polycyclic aromatic hydrocarbons

Solvation of coronene oligomers by para-H2 molecules: the effects of size and shape

“…As in our former investigations [35][36][37] we used a united-atom model for para-hydrogen for both structural and path-integral molecular dynamics computations. This is justified by the experimental situation we are referring to, in which the coronene cations coated by hydrogen are initially generated into the cryogenic medium of helium nanodroplets.…”

“…In this study we notably aim at characterizing the size of the solvation shell of hydrogen molecules coating cationic coronene oligomers. Following our earlier investigations of hydrogen uptake on individual PAH molecules, [35][36][37] we first employ geometric criteria to achieve this characterization, by examining the distribution of the (minimum) distance between the para-H 2 molecules to the various atoms of the solute. The minimum distance is a more appropriate quantity than the distance to the center of the solute owing to the strongly aspherical character of polyaromatic molecules.…”

“…As expected, the shell size varies essentially monotonically with increasing number of coating hydrogen molecules, minor deviations being due to finite size fluctuations. 36 At small coverage N o 40, limited integration of the minimum distance distribution yields a shell size that, by construction, is identical to the number of available molecules. In contrast, the Gaussian fit approximation predicts shell sizes that are actually lower, although the trends are similar.…”

“…More accurate definitions for the onset of the second shell are possible but require taking into account the finite size fluctuations, which can cause the occasional appearance of a second shell and its disappearance once another hydrogen molecule is added. 36 In particular, the first shell N max can be defined as the maximum number of hydrogen molecules that can be sustained by the system to produce a unimodal minimum distance distribution with no shoulder on the large distance side, the distribution at size N max + 1 showing a second peak or a shoulder on the large distance side.…”

“…In earlier work, we computationally examined the solvation of various carbonaceous molecules by para-hydrogen and orthodeuterium, including coronene and other PAHs ranging from benzene to circumcoronene, 35 as well as fullerenes. 36,37 The carbonaceous dopants were modeled at the atomistic level but treated as rigid, the hydrogen molecules being described as pointlike and interacting with each other through the long established Silvera-Goldman (SG) potential. 38 The interaction between the dopant and the hydrogen molecules was modeled from a pairwise additive contribution from repulsion and dispersion terms, plus a vectorial polarization term acting on the solvent molecules arising from the multipolar distribution on the dopant set as partial atomic charges.…”