Abstract Submitted for the MAR06 Meeting of The American Physical Society Quantum Monte Carlo Calculations of Excitations in Hydro- genated Germanium Clusters JORDAN VINCENT, Physics Dept. at UIUC,

Submitted for the MAR06 Meeting of The American Physical Society Quantum Monte Carlo Calculations of Excitations in Hydrogenated Germanium Clusters JORDAN VINCENT, Physics Dept. at UIUC, JEONGNIM KIM, NCSA/MCC at UIUC, RICHARD MARTIN, Physics Dept. at UIUC — Quantum Monte Carlo (QMC) calculations are presented for energies of ground and excited states of Ge atom and hydrogen passivated closed-shell molecules and clusters: GeH4, Ge2H6, Ge5H12, Ge10H16 and Ge29H36. We compare the results for excitations with previous QMC and time-dependant Density Functional Theory (TDDFT) done for the corresponding Silicon clusters [1,2]; in particular; we find that preliminary results for lowest excitation enregy of Ge29H36 5.08[29]eV is lower than the gap 5.4eV reported for Si[2]. Core-valence partitioning for Ge is implemented by replacing the core-states with a Hartree-Fock pseudopotential plus a Core Polarization Potential (CPP)[3]. Core-valence correlation treated by the CPP is shown to be essential for accurate atomic energies and significant for the molecules, but smaller in the clusters. [1] Porter et. al., PRB 64, 035320 (2001). [2] Williamson et. al., PRL 89, 196803 (2002). [3] Shirley and Martin, PRB 47, 15413 (1993) Jordan Vincent Physics Dept. at UIUC Date submitted: 30 Nov 2005 Electronic form version 1.4