Spectroscopic characterization of theXthinsp;1Sgr;+0andCthinsp;1Pgr;1states of the ZnKr molecule

摘要

TheXthinsp;1Sgr;+0andCthinsp;1Pgr;1electronic states of the ZnKr van der Waals molecule have been characterized by laserhyphen;induced fluorescence spectroscopy. Spectroscopic constants, bond lengths, and dissociation energies are reported for both states. The substantial amount of data now available on Msdot;RG lsquo;lsquo;purehyphen;pgr;rsquo;rsquo; excited states, where M=Zn, Cd, and Hg and RG=Ne, Ar, Kr, and Xe is also examined critically. It is proposed that the much larger dissociation energies and shorter bond lengths of the purehyphen;pgr; states compared to the ground states is due primarily to the fact that the RG atom, approaching in the nodal plane of the diffuse M(np) orbital, feels an effective positive charge when near the contracted M(ns) lsquo;lsquo;core.rsquo;rsquo; In the cases wherereandDehave both been determined, effective core charges are calculated to be 0.85ndash;1.00 using a simple model potential with only a lsquo;lsquo;corehyphen;ion/inducedhyphen;dipolersquo;rsquo; attractive term. Fundamental vibrational frequencies calculated with the same potential also agree well with values determined experimentally for the purehyphen;pgr; states. Detailed comparisons of the properties of the purehyphen;pgr; states of Nasdot;RG vs those of Znsdot;RG, Cdsdot;RG, and Hgsdot;RG molecules indicate that in the latter cases, the interaction also involves lsquo;lsquo;back polarizationrsquo;rsquo; of the M(ns) core electron away from the approaching RG atom, which increases the apparent M(ns) charge.