Index of content:
Volume 115, Issue 16, 22 October 2001
115(2001); http://dx.doi.org/10.1063/1.1412467View Description Hide Description
HHeF, a first predicted chemically-bound helium compound, is a metastable species that disintegrates by tunneling through energy barriers into He+HF and H+He+F. The reaction paths for these decomposition processes are calculated with single-configurational Møller-Plesset (MP2) and multiconfigurational quasidegenerate MCQDPT2/MCSCF(10,6) electronic structure methods. The lifetime of HHeF, estimated using a one-dimensional model along the minimum energy path and the semiclassical WKB approximation, is more than 120 ps, that of DHeF is 14 ns. The relatively long lifetimes are encouraging for the preparation prospects of this helium compound.
115(2001); http://dx.doi.org/10.1063/1.1413513View Description Hide Description
Orbital–vibronic coupling constants were calculated and analyzed using clustermodels with symmetry at the B3LYP level of density functional theory to aid the understanding of the electron–phonon interaction mechanism in magnesium diborate, a new binary superconductor with of 39 K. How the frontier orbitals couple with the modes of molecular vibration in the clustermodels is discussed with an emphasis on the symmetry of the relevant molecular orbitals and vibrations.