Singlet and triplet states of the sandwich-type Be2B6 and Be2B7+ clusters. A test for the electron counting rules of aromaticity

2020 ◽  
Vol 44 (45) ◽  
pp. 19780-19788
Author(s):  
Slađana Đorđević ◽  
Slavko Radenković
Keyword(s):  
Triplet States ◽  
Electron Counting ◽  
Counting Rules ◽  
Sandwich Type ◽  
Singlet And Triplet States

The studied complexes exhibit double aromaticity in their triplet states in line with the predictions of Hückel and Baird's rules.

A computational study of potential molecular switches that exploit Baird's rule on excited-state aromaticity and antiaromaticity

2014 ◽  
Vol 174 ◽  
pp. 105-124 ◽  
Author(s):  
H. Löfås ◽  
B. O. Jahn ◽  
J. Wärnå ◽  
R. Emanuelsson ◽  
R. Ahuja ◽  
...  
Keyword(s):  
Single Molecule ◽  
Density Functional ◽  
Computational Study ◽  
Triplet States ◽  
Functional Theory ◽  
Counting Rules ◽  
Singlet And Triplet States ◽  
Back Transfer ◽  
Thermal Stability Of ◽  
Electronic Ground

A series of tentative single-molecule conductance switches which could be triggered by light were examined by computational means using density functional theory (DFT) with non-equilibrium Green's functions (NEGF). The switches exploit the reversal in electron counting rules for aromaticity and antiaromaticity upon excitation from the electronic ground state (S0) to the lowest ππ* excited singlet and triplet states (S1 or T1), as described by Hückel's and Baird's rules, respectively. Four different switches and one antifuse were designed which rely on various photoreactions that either lead from the OFF to the ON states (switches 1, 2 and 4, and antifuse 5) or from the ON to the OFF state (switch 3). The highest and lowest ideal calculated switching ratios are 1175 and 5, respectively, observed for switches 1 and 4. Increased thermal stability of the 1-ON isomer is achieved by benzannulation (switch 1B-OFF/ON). The effects of constrained electrode–electrode distances on activation energies for thermal hydrogen back-transfer from 1-ON to 1-OFF and the relative energies of 1-ON and 1-OFF at constrained geometries were also studied. The switching ratio is strongly distance-dependent as revealed for 1B-ON/OFF where it equals 711 and 148 when the ON and OFF isomers are calculated in electrode gaps with distances confined to either that of the OFF isomer or to that of the ON isomer, respectively.

The bounding energy for singlet and triplet states of the negative muonium ion

2011 ◽  
Vol 30 (0) ◽  
pp. 240-245 ◽  
Author(s):  
М. Гайсак ◽  
М. Гнатич ◽  
Ю. Федорняк
Keyword(s):  
Triplet States ◽  
Singlet And Triplet States

scholarly journals Magnetic shielding paints an accurate and easy-to-visualize portrait of aromaticity

2021 ◽  
Author(s):  
Peter Karadakov ◽  
Brett VanVeller
Keyword(s):  
Magnetic Shielding ◽  
Resonance Structures ◽  
Electron Counting ◽  
Counting Rules

Chemists are trained to recognize aromaticity semi-intuitively, using pictures of resonance structures and Frost-Musulin diagrams, or simple electron-counting rules such as Hückel’s 4n + 2/4n rule. To quantify aromaticity one...

An ab initio study on some low-lying singlet and triplet states of SbO2+ and quartet states of SbO2

2006 ◽  
Vol 429 (4-6) ◽  
pp. 365-370 ◽  
Author(s):  
Edmond P.F. Lee ◽  
John M. Dyke ◽  
Foo-tim Chau ◽  
Wan-ki Chow ◽  
Daniel K.W. Mok
Keyword(s):  
Ab Initio ◽  
Triplet States ◽  
Ab Initio Study ◽  
Singlet And Triplet States

REDUCED MULTIREFERENCE COUPLED-CLUSTER METHOD AND ITS APPLICATION TO THE PYRIDYNE DIRADICALS

2008 ◽  
Vol 07 (04) ◽  
pp. 805-820 ◽  
Author(s):  
XIANGZHU LI ◽  
JOSEF PALDUS
Keyword(s):  
Molecular Geometry ◽  
External Source ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Triplet States ◽  
Correlation Effects ◽  
Spin Multiplicity ◽  
Triplet Splitting ◽  
Singlet And Triplet States

The reduced multireference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that employs a modest-size MR CISD wave function as an external source for the most important (primary) triples and quadruples in order to account for the nondynamic correlation effects in the presence of quasidegeneracy, and which is further perturbatively corrected for the remaining (secondary) triples, RMR CCSD(T), is employed to compute the molecular geometry and the energy of the lowest-lying singlet and triplet states, as well as the corresponding singlet–triplet splitting, for all possible isomers of the m, n-pyridyne diradicals. A comparison is made with earlier results that were obtained by other authors, and the role of the multireference effects for both the geometry and the spin multiplicity of the lowest state, as described by the RMR-type methods, is demonstrated on the example of 2,6- and 3,5-pyridynes.

The trion spin-singlet and -triplet states in ZnSe single quantum wells

2000 ◽  
Vol 214-215 ◽  
pp. 832-836 ◽  
Author(s):  
O Homburg ◽  
P Michler ◽  
K Sebald ◽  
J Gutowski ◽  
H Wenisch ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Triplet States ◽  
Single Quantum ◽  
Spin Singlet ◽  
Singlet And Triplet States
Sign in / Sign up

Export Citation Format

Share Document