|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|5431484||1398022||2018||8 صفحه PDF||سفارش دهید||دانلود کنید|
We present a combined experimental and theoretical study of the self-diffusion of ammonia on exfoliated graphite. Using neutron time-of-flight spectroscopy we are able to resolve the ultrafast diffusion process of adsorbed ammonia, NH3, on graphite. Together with van der Waals corrected density functional theory calculations we show that the diffusion of NH3 follows a hopping motion on a weakly corrugated potential energy surface with an activation energy of about 4Â meV which is particularly low for this type of diffusive motion. The hopping motion includes further a significant number of long jumps and the diffusion constant of ammonia adsorbed on graphite is determined with D=3.9â 10â8m2/s at 94Â K.
Journal: Carbon - Volume 126, January 2018, Pages 23-30