J053033 グラファイト表面における水分子の散乱挙動の解析(〔J053-03〕マイクロ・ナノスケールの熱流体現象(3))

Abstract

In recent years, water transport in nano-scale devices is of technological importance. Gas behavior in nano-scale devices is classified as rarefied gas flow, which depends a great deal on gas-surface interactions. Therefore, we investigated scattering behavior of water molecules on graphite surface, by the molecular beam technique. Previous studies of water - graphite scattering behavior targeted high translational energy (> 300 meV) of incident molecules. Since the adsorption energy of a water molecule on graphite surface is reported as 100 to 150 meV, we targeted low incident energy (35-130 meV) and analyzed the incident energy dependence of scattering behavior and incident energy. Our findings are summarized as follows. First, water molecules with low incident energy (35 - 43 meV) scatter more diffusively than molecules with high incident energy (64 - 130 meV). Second, water scattering is different from that of simple molecules even for high incident energy (130 meV). These result suggest that the surface potential effects need to be considered for the analysis of water behavior in nano-scale devices.