Field evaporation of Ir in hydrogen atmosphere

Abstract

In this paper, some of the data for interaction of Ir atoms with hydrogen in a high electric field obtained with a high-resolution pulsed-laser time-of-flight atom-probe field ion microscope are presented. A model is proposed that under these conditions iridium evaporates in the most part as IrH 2+ and IrH 2 2+ which are subsequently field-dissociated as iridium and hydrogen ions. We present ab initio calculations in a density functional theory for H–Ir, including external homogeneous electrostatic fields, too. The energy barrier for dissociating Ir–H complex decreases gradually with increasing field until it vanishes at about 18 V/nm . The theoretical data obtained are in good agreement with the experiment; our hypothesis can be regarded as highly probable.