The simplest metastable Xe-containing compound HXeH has been theoretically investigated using highly-accurate CASPT2-level electronic structure calculations taking the relativistic effects into account. A new three-dimensional global potential energy surface has been developed and time-dependent wave packet quantum dynamics calculations were then performed to obtain vibrational energy levels of the metastable states for the HXeH, HXeD and DXeD systems. It has been found that low-lying vibrational states below and just above the H + Xe + H dissociation limit have extremely long lifetimes in a nanosecond time scale. The present theoretical results suggest that these rare-gas containing molecules can experimentally be detected in the gas phase. (C) 2007 Elsevier B.V. All rights reserved.