Structures and stability of medium silicon clusters. II. Ab initio molecular orbital calculations of Si12-Si20.

AB Initio Calculations of NMR Spectra for H20114C9N4 As A New Nanosemiconductor Molecule

BCN compounds have been researched theoretically and experimentally widely. In this paper, weintroduce the theoretical prediction of ternary B-C-N compounds. NMR spectroscopy was employedextensively to study these ternary nanostructures. We discuss the utilization of chemical shiftinformation as well as ab initio calculations of nuclear shielding for H20134C9N4 structuredetermination. We calcul...

Structures and stabilities of small silicon clusters: Ab initio molecular-orbital calculations of Si7â•fiSi11

Finite-temperature behavior of small silicon and tin clusters: An ab initio molecular dynamics study

The finite-temperature behavior of small silicon and tin clusters Si10, Si15, Si20, Sn10, and Sn20 is studied using isokinetic Born-Oppenheimer molecular dynamics. We find that the low-lying structures for all the clusters are built upon a highly stable tricapped trigonal prism unit which is seen to play a crucial role in the finite-temperature behavior. The thermodynamics of small tin clusters...

First-principles calculations of metal stabilized Si20 cages

It is well known that sp bonding in carbon can result in stable cage structures, but pure Si clusters with similar cage structures are unstable. Using first-principles calculations, we show that a dodecahedral cage of silicon can be stabilized dynamically as well as energetically by doping with Ba, Sr, Ca, Zr, and Pb atoms to create structures of silicon similar to that of the smallest carbon f...

An Ab initio and chemical shielding tensors calculations for Nucleotide 5’-Monophosphates in the Gas phase

Structural and magnetic properties of purine and pyrimidine nucleotides (CMP, UMP, dTMP, AMP, GMP, IMP) were studied at different levels of ab initio molecular orbital theory. These calculations were performed at the hartree-fock level and density functional B3LYP methods. Geometries were fully optimized by following Cs symmetry restrictions. The standard 6-31G** basis set which includes polari...