Chemical dynamics simulation of Ne atom scattering off a squalane surface

Yuxing Peng, Lei Liu, Zhen Cao, Shu Li, Oleg A. Mazyar, William L. Hase, Tianying Yan

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

A chemical dynamics simulation was performed to study collisions between neon (Ne) atoms and a liquid squalane (2,6,10,15,19,23-hexamethyltetracosane) surface. Ten thousand trajectories were calculated, with an incident energy of 10 kcal/mol, incident polar angle 45° with respect to the surface normal, and random azimuthal angle. The final energy distribution, angular distribution, and impact sites were determined and analyzed. The incident Ne atoms have short residence times on the surface with most atoms successfully scattering within 3-7 ps. Due to thermal fluctuations of the surface, the incident energy is dissipated efficiently, and more than 60% of the initial energy of the Ne atoms is transferred with three or more "kicks" on the surface. For in-plane scattered Ne atoms with a final polar angle of 45°, the energy transfer is 58% ± 8%, which is in good agreement with the experimental value of 60% (J. Chem. Phys. 1993, 99, 7056). A bimodal energy distribution is observed for both in-plane and out-of-plane scattering, with a much larger Boltzmann component for out-of-plane scattering as compared to in-plane scattering. The incident Ne atoms are found to primarily impinge the terminal methyl groups of the squalane molecules, and such impact probability is correlated with the interfacial structure of the squalane surface. Comparison with previous study of Ne atom scattering off a H-terminated alkyl thiol self-assembled monolayer (H-SAM) surface shows that energy transfer to squalane is less efficient than to the H-SAM, because flexible intermolecular couplings of the alkyl thiol chains of the H-SAM provide efficient dissipation channels to accommodate the incident Ne atom's energy.

Original languageEnglish
Pages (from-to)20340-20346
Number of pages7
JournalJournal of Physical Chemistry C
Volume112
Issue number51
DOIs
StatePublished - 2008

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