Are Tetra[gold(I)]phosphonium Cations [(LAu)4P]+ Non-obedient to the LeBel-van’t Hoff Rule?

2008 ◽  
Vol 63 (7) ◽  
pp. 853-859 ◽  
Author(s):  
Hubert Schmidbaur
Keyword(s):  
Ground State ◽  
Central Element ◽  
Theoretical Studies ◽  
Tetrahedral Structure ◽  
Pyramidal Structure ◽  
Onium Salts ◽  
Central Elements ◽  
Aurophilic Interactions ◽  
Molecular And Electronic Structure ◽  
Phosphonium Cations

Recent theoretical studies of the molecular and electronic structure of tetra[(phosphine)gold(I)]- phosphonium cations, [(H3PAu)4P]+, gave contradictory results favoring either a classical tetrahedral or a unique square-pyramidal structure of the PAu4 unit. A tetrahedral structure had previously been confirmed for the corresponding ammonium cations [(Ph3PAu)4N]+, while a square-pyramidal structure was discovered for the corresponding arsonium cations [(Ph3PAu)4As]+, but there is as yet no unequivocal experimental evidence for the structure of phosphonium cations like [(Ph3PAu)4P]+ in an innocent environment. - In this account the structural chemistry of this class of onium salts and related species is reviewed. The data accumulated to date provide virtually compelling evidence that the phosphonium cations should have a ground state with a square pyramidal PAu4 core unit, provided that no external constraints are imposed. For large central elements (P, As), aurophilic interactions appear to drive the reorganization from tetrahedral to square-pyramidal skeletons in which a maximum number of short Au---Au contacts can be maintained. For the small central element N, similar interactions are already realized in the tetrahedral structure.

REVIEW ON THEORETICAL STUDIES OF SUPERHEAVY NUCLEI

2006 ◽  
Vol 15 (07) ◽  
pp. 1587-1599 ◽  
Author(s):  
ZHONGZHOU REN ◽  
DINGHAN CHEN ◽  
CHANG XU
Keyword(s):  
Ground State ◽  
Large Mass ◽  
Mass Region ◽  
Superheavy Nuclei ◽  
Theoretical Studies ◽  
Shape Coexistence ◽  
Good Test ◽  
Α Decay ◽  
The Stability ◽  
Theoretical Results

Superheavy elements have provided a good test of the validity of both nuclear structure models and nuclear decay models in a large mass region. We firstly review the recent progress on theoretical studies of superheavy nuclei. Emphasis is placed on the structure and decay of superheavy nuclei. Then theoretical results of odd-odd nuclei with Z = 109 - 115 are presented and discussed. It is clearly demonstrated that there is shape coexistence for the ground state of many superheavy nuclei from different models and many superheavy nuclei are deformed. In some cases superdeformation can become the ground state of superheavy nuclei and it is important for future studies of superheavy nuclei. This can lead to the existence of low-energy isomers in the superheavy region and it plays an important role for the stability of superheavy nuclei. As α-decay and spontaneous fission plays a crucial role for identifications of new elements, we also review some typical models of α-decay half-lives and spontaneous fissions half-lives. Some new views on superheavy nuclei are presented.

Molecular and electronic structure of ozone and thiozone from LCAO local density calculations

1985 ◽  
Vol 63 (7) ◽  
pp. 1982-1987 ◽  
Author(s):  
Mario Morin ◽  
Aniko E. Foti ◽  
Dennis R. Salahub
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
Local Minimum ◽  
Local Density ◽  
Molecular And Electronic Structure ◽  
Ground State Geometry ◽  
Good Agreement

LCAO local density calculations for ozone yield a ground state geometry in good agreement with experiment (R = 1.27 Å vs. 1.278 Å (exp.), θ = 117.5° vs. 116.8° (exp.)). A second local minimum is found about 45 kcal/mol higher for a cyclic geometry (R = 1.44 Å, θ = 60°). For S3 the calculations predict a bent ground state (R = 2.00 Å, θ = 116°) with the cyclic geometry (R = 2.125 Å, θ = 58°) about 15 kcal/mol higher.

scholarly journals Synthesis, molecular and electronic structure of an incomplete cuboidal Re3S4 cluster with an unusual quadruplet ground state

2012 ◽  
Vol 48 (21) ◽  
pp. 2713 ◽  
Author(s):  
Pavel A. Petrov ◽  
Alexander V. Virovets ◽  
Artem S. Bogomyakov ◽  
Rosa Llusar ◽  
Carlos J. Gómez-García ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
Molecular And Electronic Structure

scholarly journals Experimental and theoretical studies of the reactions of ground-state sulfur atoms with hydrogen and deuterium

2017 ◽  
Vol 147 (13) ◽  
pp. 134302 ◽  
Author(s):  
Kristopher M. Thompson ◽  
Yide Gao ◽  
Paul Marshall ◽  
Han Wang ◽  
Linsen Zhou ◽  
...  
Keyword(s):  
Ground State ◽  
Theoretical Studies ◽  
Experimental And Theoretical Studies

The (K−,π−) and (π+, K+) Reactions and Λ-Hypernuclear Polarization

1994 ◽  
Vol 117 ◽  
pp. 17-53 ◽  
Author(s):  
K. Itonaga ◽  
T. Motoba ◽  
M. Sotona
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Cross Sections ◽  
Ground State ◽  
Weak Decay ◽  
Angular Distributions ◽  
Theoretical Studies ◽  
Excitation Functions ◽  
Unnatural Parity ◽  
Natural Parity

The theoretical studies of (K−, π−) and (π+, K+) reactions on p-shell targets are presented in the DWIA framework with use of the elementary spin-nonflip and spin-flip amplitudes. Calculations can explain the available experimental data of excitation functions and angular distributions of the (K−, π−) reactions at pK−=800 MeV/c and the (π+, K+) reactions at pπ+ = 1.04 GeV/c. Characteristic and distinguished features of the excitation functions and cross sections are exhibited. Especially it is demonstrated that the (K−, π−) reactions at pK−=1.1 GeV/c and 1.5 GeV/c can excite the unnatural parity states with comparable strength to the natural parity ones. Further interesting is that the (π+, K+) and (K−, π−) reactions with ∼1 GeV/c incident beams can be shown to produce very large polarizations of the produced hypernuclear states. Taking the subsequent deexcitation processes of the excited states into account, we have evaluated the hypernuclear polarization and Λ-spin polarization of the ground state and/or the ground-doublet states at the hypernuclear weak-decay stage, which would play a role in the hypernuclear coincidence experiment.

scholarly journals SYMMETRIC SQUARE-CENTRAL ELEMENTS IN PRODUCTS OF ORTHOGONAL INVOLUTIONS IN CHARACTERISTIC TWO

2017 ◽  
Vol 96 (3) ◽  
pp. 412-425
Author(s):  
A.-H. NOKHODKAR
Keyword(s):  
Central Element ◽  
Central Elements ◽  
Symmetric Square ◽  
Characteristic Two

In characteristic two, some criteria are obtained for a symmetric square-central element of a totally decomposable algebra with orthogonal involution, to be contained in an invariant quaternion subalgebra.

Sign in / Sign up

Export Citation Format

Share Document