A theoretical model for the scattering of I2 molecule from a perfluoropolyeter liquid surface

Abstract

Neste trabalho desenvolvemos um modelo do potencial de interação para simulação de experimentos de espalhamento de um feixe de moléculas de I2 sobre a superfície do líquido polimérico poliéterperfluorado e resolvemos a dinâmica do processo de colisão usando o método das trajetórias clássicas. A energia transferida no processo para os modos vibracionais da molécula de I2 e para o líquido foram investigados como função dos parâmetros do potencial.In order to simulate experimental results of scattering of an I2 beam from liquid perfluorpolyeter ( PFPE ) surface we developed a model potential for the gas-polymer interaction at the liquid surface and solved the dynamics of the collision process by the classical trajectory method. The energy transferred in the process to the vibrational mode of the I2 molecule and to the liquid surface was investigated as a function of potential parameters.

A 2d model of the dynamic of the collision: i2-polymeric liquid surfaces of perfluorinatedpolyether (PFPE), polydimetilsiloxane (PDMS) and squalane

“…Experimental results of gas-liquid scattering 6,9,10,18 have shown that for higher values of incident energy E of the atom or molecule, the IS process dominates and for the lower values of E a significant amount of the incident gas species is temporarily adsorbed. This result, demonstrated in a previous study of the dynamic of I 2 -PFPE scattering 14 is confirmed by the simulation. This is showed in Figure 5, in which the temporal variation of the parameter ρ, as defined in Figure 1, is plotted for the surface models of PDMS (5a and 5d), PFPE (5b and 5e) and squalane (5c and 5f), for a particular set of 10 consecutive trajectories randomly chosen with initial energy of 40 kJ mol -1 (Figures 5a, 5b and 5c) and 10 kJ mol -1 (Figures 5d, 5e, and 5f).…”

“…Experiments have shown that PDMS, squalane and PFPE have axial protruding -CH 3 and -CF 3 groups, respectively, in a trans configuration and the orientation of these groups also suggests some degree of order in the liquid surface. [12][13][14][15] Therefore, we describe in this model the oscillations of the protruding groups, taken as a -CH 3 group in PDMS and squalane and a -CF 3 group in PFPE, as the oscillations of a set of three coupled harmonic oscillators of mass M corresponding to the mass of each group. The frequencies ν 1 and ν 2 of the oscillators are the two lowest frequencies observed in the Raman spectra of these compounds.…”

Фазовий Перехід Першого Роду В Рамках Коміркової Моделі Плину: Області Зміни Хімічного Потенціалу Та Відповідні Густини

“…Therefore, the second summand, 𝑀 , in the right-hand sides of Eqs. ( 25), (28), and ( 30) is much smaller than the third term and can be neglected.…”

“…In some cases, modifications of the Morse function were made [23][24][25][26] in order to improve the numerical results. Although the Morse potential was traditionally used to model covalently bound diatomic molecules [27][28][29], it is also applied to estimate non-bounding interactions [30,31]. This potential is qualitatively similar to the Lennard-Jones potential, but they are quite different from the quantitative point of view.…”

Um modelo para a superfície líquida no estudo da dinâmica do espalhamento de Xe e Ne pelo esqualano

“…Nesse experimento, a molécula é usada como uma sonda para investigar as características de cada superfície, através dos seus espectros, vibracional e rotacional, de fluorescência induzida por laser. As caraterísticas dinâmicas gerais observadas neste experimento foram satisfatoriamente reproduzidas por Leal e colaboradores 14,15 em um modelo onde o potencial de interação molécula-superfície inclui as interações de três corpos e para o líquido é empregada uma superfície bidimensional. O modelo aqui proposto para o espalhamento átomo-superfície em três dimensões é mais simples e inclui mais graus de liberdade para a descrição da superfície líquida.…”