On the Structure of Lead(II) Complexes in Aqueous Solutions. III. Hexanuclear Clusters

2002 ◽  
Vol 67 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Experimental Techniques ◽  
Hexanuclear Clusters ◽  
Semiempirical Mndo

Optimum geometries based on experimental structures and corresponding electronic structures of [Pb6(μ3-OH)8]4+ and [Pb6O(μ3-OH)6]4+ clusters as well as of their hydrated [Pb6(μ3-OH)8(H2O)6]4+ and [Pb6O(μ3-OH)6(H2O)6]4+ analogues are investigated using the semiempirical MNDO method of quantum chemistry. Direct Pb-Pb and O-O bonds are vanishing in the systems under study. Small differences in interatomic Pb-Pb and Pb-O distances between these clusters indicate that they cannot be distinguished by recent experimental techniques in solution. Both the mentioned structures are stable and might coexist in solution.

On the Structure of Lead(II) Complexes in Aqueous Solutions. I. Trinuclear Clusters

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Model Systems ◽  
Trinuclear Clusters ◽  
The Stability ◽  
Semiempirical Mndo

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.

scholarly journals Electronic Properties of Triangle Molybdenum Disulfide (MoS2) Clusters with Different Sizes and Edges

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1157
Author(s):  
Songsong Wang ◽  
Changliang Han ◽  
Liuqi Ye ◽  
Guiling Zhang ◽  
Yangyang Hu ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Electronic Properties ◽  
Absorption Spectra ◽  
Molecular Orbital ◽  
Electronic Structures ◽  
Edge States ◽  
Frontier Orbitals ◽  
Edge Structure ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital

The electronic structures and transition properties of three types of triangle MoS2 clusters, A (Mo edge passivated with two S atoms), B (Mo edge passivated with one S atom), and C (S edge) have been explored using quantum chemistry methods. The highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap of B and C is larger than that of A, due to the absence of the dangling of edge S atoms. The frontier orbitals (FMOs) of A can be divided into two categories, edge states from S3p at the edge and hybrid states of Mo4d and S3p covering the whole cluster. Due to edge/corner states appearing in the FMOs of triangle MoS2 clusters, their absorption spectra show unique characteristics along with the edge structure and size.

Electronic Structures of Crystalline and Aqueous Solutions of LiBr, NaBr, KBr, and KBrO3:  In Situ Br L-Edge Near-edge X-ray Absorption Fine Structure

2003 ◽  
Vol 107 (46) ◽  
pp. 12562-12565 ◽  
Author(s):  
Shuji Matsuo ◽  
Ponnusamy Nachimuthu ◽  
Dennis W. Lindle ◽  
Hisanobu Wakita ◽  
Rupert C. C. Perera
Keyword(s):  
Fine Structure ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

The Chemisorption of C on Al(111)

1998 ◽  
Vol 05 (02) ◽  
pp. 537-543
Author(s):  
E. E. Mola ◽  
G. A. Appignanesi ◽  
J. L. Vicente
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Interaction Energy ◽  
Adsorption Site ◽  
Mndo Method ◽  
Scanning Tunneling ◽  
Surface Site ◽  
Tunneling Microscopy ◽  
Semiempirical Mndo

The chemisorption of C atoms on Al(111) was studied by means of the semiempirical MNDO method. The incorporation of the C adatom into the clusters was considered and the most favorable chemisorption site was evaluated. The hcp in-surface site was identified as the most stable adsorption site, in agreement with recent scanning tunneling microscopy (STM) experiments. This fact allowed us to use the MNDO method to evaluate the interaction energy of two chemisorbed C atoms in order to understand the observed formation of an ordered carbon underlayer. The low mobility of single isolated C adatoms revealed in STM experiments is also discussed.

Sign in / Sign up

Export Citation Format

Share Document