EUCMOS 2008

     The family of noble-gas containing hydrides of common structure HNgY amounts 23, including the first argon molecule, HArF [1]. Both inorganic and organic Y fragments are involved in such molecules, the organic acetylenic and diacetylenic species being recently synthesized [2-5]. These examples suggest that new such molecules will be found in future. The HNgY molecules have very characteristic properties as suggested by computational methods: linear bonding is involved around the noble gas atom, the (HNg)⁺Y^- structure plays a central role in bonding, and they possess very high dipole moments. The practical consequences of the properties of these molecules are versatile, and will be discussed. First, the H-Ng stretching absorption intensity is quite large, and the formation of the HNgY molecules upon hydrogen atom mobilisation can be monitored with great sensitivity yielding reliable measures for the H/D mobility [6]. Secondly, exceptionally large matrix site effects due to their large dipoles are found for these molecules, giving tools to probe experimentally the local environments of the embedded molecules [7]. Selective and reversible light control of formation of HXeCC radical will be discussed [8].