کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5424944 | 1395842 | 2007 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Methods for calculating the desorption rate of an isolated molecule from a surface: Water on MgO(0Â 0Â 1)
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
Water - آبMagnesium oxides - اکسید منیزیمEquilibrium thermodynamics and statistical mechanics - ترمودینامیک تعادل و مکانیک آماریAtom-solid interactions - تعامل اتمی جامدPhysical adsorption - جذب فیزیکیThermal desorption - دفع حرارتیMolecular dynamics - دینامیک ملکولی یا پویایی مولکولیSemi-empirical models and model calculations - مدل های نیمه تجربی و محاسبات مدل
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
We present two types of Molecular Dynamics (MD) simulation for calculating the desorption rate of molecules from a surface. In the first, the molecules move freely between two surfaces, and the desorption rate is obtained either by counting the number of desorption events in a given time, or by looking at the average density of the molecules as a function of distance from the surface and then applying transition state theory (TST). In the second, the potential of mean force (PMF) for a molecule is determined as a function of distance from the surface and the desorption rate is obtained by means of TST. The methods are applied to water on the MgO(0Â 0Â 1) surface at low coverage. Classical potentials are used so that long simulations can be performed, to minimise statistical errors. The two sets of MD simulations agree well at high temperatures. The PMF method reproduces the 0Â K adsorption energy of the molecule to within 5Â meV, and finds that the well depth of the PMF is not linear with temperature. This implies the prefactor frequency f in the Polanyi-Wigner equation is a function of temperature, increasing at lower temperatures due to the reduction of the available configuration space associated with an adsorbed molecule compared with a free molecule.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 601, Issue 21, 1 November 2007, Pages 5016-5025
Journal: Surface Science - Volume 601, Issue 21, 1 November 2007, Pages 5016-5025
نویسندگان
H. Fox, M.J. Gillan, A.P. Horsfield,