Cserfalvi T, Mezei P
Aqua-Concorde Analytical R& D Laboratory, Bosnyak u. 11, H-1145, Budapest, Hungary.
Anal Bioanal Chem. 1996 Jul;355(7-8):813-9. doi: 10.1007/s0021663550813.
Cathode fall ( U(cf)), cathodic current density and atomic emission intensities originating from metal salts in the electrolyte cathode were measured as a function of different discharge parameters. Emission intensities in function of cathode fall indicate a potential barrier in the sputtered mass flux. This means that the primary particles of the cathode sputtering are of positive charge and the cathode fall including its internal variables is the most important factor. The measured current density and the U(cf) as a function of pressure are in accordance with the low pressure data in the literature. The observed decrease of the U(cf) with decreasing pH was explained by a model in that the secondary electron emission coefficient of the cathode (gamma) is controlled through a reaction net of competing reactions of different electron scavengers involving the hydroxonium ions of the cathode solution. The model revealed two different electron emission processes of the electrolyte cathode, an emission coupled with hydrated electrons is dominating below pH 2.5 while a proton-independent emission of poor efficiency is working above pH 3. Our model fits to the reported yields of the ultimate products both in the solution and in the gas phase and offers a calculation of gamma and U(cf) in the function of the cathode acidity. The model provides two other independent gamma calculation methods based on product analysis data.
测量了阴极压降（U(cf)）、阴极电流密度以及源自电解质阴极中金属盐的原子发射强度随不同放电参数的变化情况。发射强度随阴极压降的变化表明溅射质量通量中存在一个势垒。这意味着阴极溅射的初级粒子带正电荷，并且包括其内部变量的阴极压降是最重要的因素。测量得到的电流密度和作为压力函数的U(cf)与文献中的低压数据相符。观察到的U(cf)随pH值降低而减小的现象，通过一个模型进行了解释，该模型认为阴极的二次电子发射系数（γ）是由涉及阴极溶液水合氢离子的不同电子清除剂的竞争反应网络所控制的。该模型揭示了电解质阴极的两种不同电子发射过程，在pH值低于2.5时，与水合电子耦合的发射占主导，而在pH值高于3时，效率较低的与质子无关的发射起作用。我们的模型与报道的溶液和气相中最终产物的产率相符合，并提供了γ和U(cf)随阴极酸度变化的计算方法。该模型还基于产物分析数据提供了另外两种独立的γ计算方法。
