Accession Number : ADA258693


Title :   Theoretical and STM Studies of the Electronic Structure of Metal/Semiconductor/Hydrogen Systems


Descriptive Note : Final rept. 1 Feb 1991-14 Aug 1992


Corporate Author : STEVENS INST OF TECH HOBOKEN NJ DEPT OF CHEMISTRY AND CHEMICAL ENGINEERING


Personal Author(s) : Ermler, Walter C


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a258693.pdf


Report Date : 19 Nov 1992


Pagination or Media Count : 76


Abstract : The structure of atomic clusters is investigated using methods of ab initio quantum chemistry in conjunction with scanning tunneling microscopy (STM) . Gold sols are imaged via STM and their sizes characterized. Atomic resolution reveals facets, steps, and reconstructed surfaces of the sols. STM images of graphite surfaces are characterized by two mechanisms: a twisted top layer configuration and a graphite-flake contaminated tip. A crystalline tip model reproduces anomalous long range periodicity, attributed to defect-mediated tip- substate convolution. Ab initio calculations of electronic states of a 135 atom Be cluster show bulk behavior for many properties centered at the middle of the cluster. The density of states agrees well with band theory models. Full spin- orbit CI calculations of the electronic spectrum and potential energy curves of LiBe, including Rydberg states, are definitive and accurate. A procedure for the incorporation of core/valence polarization effects in all-valence electron calculations is presented for use with relativistic effective core potentials. The method allows the treatment of large clusters at the ab initio level including procedures for the inclusion of electron correlation....


Descriptors :   *METALS , *QUANTUM CHEMISTRY , *LATTICE DYNAMICS , DENSITY , LITHIUM , BERYLLIUM , GOLD , RELATIVISTIC ELECTRONS , POTENTIAL ENERGY , MOLECULAR STRUCTURE , ELECTRONIC STATES , GRAPHITE , POLARIZATION


Subject Categories : Physical Chemistry
      Atomic and Molecular Physics and Spectroscopy
      Quantum Theory and Relativity


Distribution Statement : APPROVED FOR PUBLIC RELEASE