Molecular Dynamics Simulation Study of Molecular Ejection Mechanisms:  keV Particle Bombardment of C₆H₆/Ag{111}

Abstract

Molecular dynamics simulations have been performed to gain microscopic insight into the factors that lead to molecular ejection after ion bombardment of an organic overlayer on a metal surface. The specific system modeled is benzene (C 6 H 6 ) adsorbed on Ag{111}. The kinetic energy and angular distributions of C 6 H 6 molecules obtained from the simulations match well with the experimentally measured distributions. The angular distributions of C 6 H 6 molecules show both normal and off-normal components. Analysis of individual trajectories reveal that the off-normal ejection arises from single collisions between substrate Ag atoms and C 6 H 6 molecules, while multiple collisions result in low-energy ejection along the surface normal. To separate issues of rotational and vibrational excitation from translational motion, calculations are also performed on an atomic adsorbate with a mass similar to that of C 6 H 6.

Explosive Boiling of Water Films Adjacent to Heated Surfaces: A Microscopic Description

“…Most importantly, it reasonably reproduces the experimental surface energy of Au. 27 The potential function has been used in MD studies of thermal properties of alkanethiolate overlayers on a Au surface 28 as well as molecular ejection induced by keV particle bombardment of benzene, 29 polystyrene oligomers, 30 and alkanethiolates 31 adsorbed on a Au(111) surface.…”

Theoretical Mass Spectra of PE, PP, PS and PET Polymers by QMD Methods Using the Model Molecules

“…In our calculation, we need to perform the calculation time of 6.9 hours for the (AM1) MOSCF calculation of 5 s and MD calculation of 5000 steps (for 1 trajectory). The thermal decomposition of PE, PP, PS, and PET polymers has been simulated using the model molecules {H-(CH 2 CH 2 ) 10 -H, H-(CH 2 -CH(CH 3 )) 8 -H, H-(CH 2 CH(C 6 H 5 )) 6 -H, and H-{CH 2 CH 2 -O(CO)-(C 6 H 4 )-(CO)O} 4 -H} by QMD using the AM1 method at the ground state.…”

“…Some advanced MD approach with empirical force fields [1][2][3][4][5] has been quite successful in providing quantitative agreement with high-energy particle bombardment of organic film adsorbed on a metal substrate [6][7][8][9], and the bombardment of a polyethylene crystal [10]. Another MD method with reactive force fields [11][12][13][14][15] developed to simulate chemical reactions in large atomic and molecular systems, and to model thermally-induced chemical transformations in large molecules in condensed phases [16][17][18][19][20], and thermal decomposition reactions in polymers [21,22].…”

Simulation of SIMS for monomer and dimer of lignin under the assumption of thermal decomposition using QMD method

“…The MD approach without MO method has also been quite successful in providing quantitative agreement with experimental energy and angular distributions of sputtered particles from a solid, 1 the high-energy particle bombardment of organic film adsorbed on a metal substrate, [2][3][4][5] and a polyethylene crystal. 6 Normal MD methods use the empirical potential functions [7][8][9][10][11] to solve the motion equations.…”