Molecular dynamics simulations of reactive neutral chemistry in an argon‐methane plasma

Abstract

Molecular dynamics simulations are performed to study the reactions in the volume of a low-pressure methane plasma diluted in argon. In the first step, a 1D fluid model is used to determine the initial molar fractions of initial species. The obtained composition thus becomes the input for the reactive molecular dynamics simulations. The study is carried out at 300, 400, 500, and 1000 K. Increasing the temperature increases the range of different molecules formed. The time evolution of C 2 H and CH 3 and the different reaction pathways leading to larger molecules show that C 2 H is the main precursor and CH 3 is the main intermediate precursor for the formation of large molecules.

Molecular dynamics approach for the calculation of the surface loss probabilities of neutral species in argon–methane plasma

“…Moreover, species such as C 4 H 2 , C 4 H 3 , and C 6 H 3 are widely known in hydrocarbon plasmas for contributing to the growth of films and large molecules. [13,17,18,73] In a previous study, [30] their importance, as well as the one of C 6 H 4 , was reported for the growth of large molecules in the volume phase. This means that the amount of reactive and nonreactive volatile products is significant and therefore cannot be neglected.…”

“…Note: Argon is not included in our simulations. [30] F I G U R E 1 (a) Stainless steel slab mimicking pristine electrodes. It is composed of 67% Fe (silver color), 17% Cr (ocher color), 14% Ni (ice blue color), and 2% Mo (tan color).…”

“…These initial neutral species interacting with the surface are obtained from a 1D kinetic model of a lowpressure Ar/4% CH 4 plasma created by a radiofrequency discharge. [28][29][30] This article is organized as follows: In the next section, we present the methodology and computational details. In Section 3, we first present the sticking probabilities of each neutral species on two types of surfaces: a pristine surface and a surface covered with a C:H film.…”

Plasma activation mechanisms governed by specific energy input: Potential and perspectives

“…[ 69 ] Molecular dynamics simulations have also pointed out the important role of ● C 2 H radicals in methane plasmas. [ 70 ]…”

“…[69] Molecular dynamics simulations have also pointed out the important role of • C 2 H radicals in methane plasmas. [70] From the above assessment, mainly C 2 H 2 and C 2 H 4 are well-suited polymerizable monomers used, for example, to deposit hard coatings or diffusion-controlling layers. [71][72][73] However, they do not bear interesting functionalities, which is why they are also mixed with nonpolymerizable gases such as N 2 , NH 3 , CO 2 , CO, H 2 O, O 2 , and so on, to incorporate functional groups in a cross-linked hydrocarbon matrix.…”