Singlet–triplet energy gap of a diarylnitroxide diradical by an accurate many-body perturbative approach

2011 ◽  
Vol 13 (10) ◽  
pp. 4709 ◽  
Author(s):  
Vincenzo Barone ◽  
Ivo Cacelli ◽  
Alessandro Ferretti ◽  
Susanna Monti ◽  
Giacomo Prampolini
Keyword(s):  
Energy Gap ◽  
Many Body ◽  
Triplet Energy ◽  
Perturbative Approach

Singlet-triplet energy gap in methylene using many-body methods

1985 ◽  
Vol 113 (3) ◽  
pp. 271-274 ◽  
Author(s):  
Samuel J. Cole ◽  
George D. Purvis ◽  
Rodney J. Bartlett
Keyword(s):  
Energy Gap ◽  
Many Body ◽  
Triplet Energy

Superconducting State

2021 ◽  
Author(s):  
Vladimir Kresin ◽  
Sergei Ovchinnikov ◽  
Stuart Wolf
Keyword(s):  
Critical Temperature ◽  
Energy Gap ◽  
Microscopic Theory ◽  
Record Values ◽  
Theoretical Treatment ◽  
Many Body ◽  
Many Body Theory ◽  
Current State ◽  
Superconducting Compounds ◽  
Body Theory

For the past almost fifty years, scientists have been trying to explain the phenomenon of superconductivity. The mechanism is the key ingredient of microscopic theory, which was developed by Bardeen, Cooper, and Schrieffer in 1957. The theory also introduced the basic concepts of pairing, coherence length, energy gap, and so on. Since then, microscopic theory has undergone an intensive development. This book provides a very detailed theoretical treatment of the key mechanisms of superconductivity, including the current state of the art (phonons, magnons, plasmons). In addition, the book contains descriptions of the properties of the key superconducting compounds that are of the most interest for science and applications. For many years, there has been a search for new materials with higher values of the main parameters, such as the critical temperature and critical current. At present, the possibility of observing superconductivity at room temperature has become perfectly realistic. That is why the book is especially concerned with high-Tc systems such as high-Tc oxides, hydrides with record values for critical temperature under high pressure, nanoclusters, and so on. A number of interesting novel superconducting systems have been discovered recently, including topological materials, interface systems, and intercalated graphene. The book contains rigorous derivations based on statistical mechanics and many-body theory. The book also provides qualitative explanations of the main concepts and results. This makes the book accessible and interesting for a broad audience.

Aggregation-induced emission (AIE)-active molecules bearing singlet oxygen generation activities: the tunable singlet–triplet energy gap matters

2019 ◽  
Vol 55 (10) ◽  
pp. 1450-1453 ◽  
Author(s):  
Chengkai Zhang ◽  
Yanqian Zhao ◽  
Dandan Li ◽  
Jiejie Liu ◽  
Heguo Han ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Cell Apoptosis ◽  
Near Infrared ◽  
Energy Gap ◽  
Intersystem Crossing ◽  
Triplet Energy ◽  
Oxygen Generation ◽  
Two Photon ◽  
Singlet Oxygen Generation ◽  
Infrared Excitation

Two-photon active photosensitizers showed relatively strong intersystem crossing facilitating 1O2 generation and cell apoptosis with near-infrared excitation.

scholarly journals Front Cover: Highly Fluorescent Emitters Based on Triphenylamine‐π‐Triazine (D‐π‐A) System: Effect of Extended Conjugation on Singlet‐Triplet Energy Gap (Asian J. Org. Chem. 9/2020)

2020 ◽  
Vol 9 (9) ◽  
pp. 1249-1249
Author(s):  
Shiv Kumar ◽  
Pachaiyappan Rajamalli ◽  
David B. Cordes ◽  
Alexandra M. Z. Slawin ◽  
Eli Zysman‐Colman
Keyword(s):  
Energy Gap ◽  
Triplet Energy ◽  
System Effect ◽  
Front Cover

scholarly journals TAO-DFT Study on the Electronic Properties of Diamond-Shaped Graphene Nanoflakes

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1236 ◽  
Author(s):  
Hong-Jui Huang ◽  
Sonai Seenithurai ◽  
Jeng-Da Chai
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Quantitative Measure ◽  
Smooth Transition ◽  
Von Neumann Entropy ◽  
Triplet Energy ◽  
Von Neumann ◽  
Graphene Nanoflakes ◽  
Radical Nature

At the nanoscale, it has been rather troublesome to properly explore the properties associated with electronic systems exhibiting a radical nature using traditional electronic structure methods. Graphene nanoflakes, which are graphene nanostructures of different shapes and sizes, are typical examples. Recently, TAO-DFT (i.e., thermally-assisted-occupation density functional theory) has been formulated to tackle such challenging problems. As a result, we adopt TAO-DFT to explore the electronic properties associated with diamond-shaped graphene nanoflakes with n = 2–15 benzenoid rings fused together at each side, designated as n-pyrenes (as they could be expanded from pyrene). For all the n values considered, n-pyrenes are ground-state singlets. With increasing the size of n-pyrene, the singlet-triplet energy gap, vertical ionization potential, and fundamental gap monotonically decrease, while the vertical electron affinity and symmetrized von Neumann entropy (which is a quantitative measure of radical nature) monotonically increase. When n increases, there is a smooth transition from the nonradical character of the smaller n-pyrenes to the increasing polyradical nature of the larger n-pyrenes. Furthermore, the latter is shown to be related to the increasing concentration of active orbitals on the zigzag edges of the larger n-pyrenes.

Substituent effects in carbocations CX+, CHX+•, and CH2X+, and in singlet and triplet carbenes CHX. Proton affinities of singlet carbenes

1985 ◽  
Vol 63 (12) ◽  
pp. 3582-3586 ◽  
Author(s):  
A. C. Hopkinson ◽  
M. H. Lien
Keyword(s):  
Energy Gap ◽  
Single Point ◽  
Substituent Effects ◽  
Basis Set ◽  
Molecular Orbital Calculations ◽  
Proton Affinities ◽  
Interaction Method ◽  
Triplet Energy ◽  
Configuration Interaction Method ◽  
Singlet Carbenes

Abinitio molecular orbital calculations with a 6-31G* basis set have been used to optimise structures for CX+, CHX+•, CHX (both singlets and triplets), H2CX+ and H3CX (X = H, CH3, NH2, OH, F, CN, and NC). Single point calculations were then performed on the 6-31G* optimised structures using a configuration interaction method involving all single and double excitations from the valence shell. Stabilisation energies for the carbocations are compared with those already reported for H2CX+. For the carbenes the single-triplet energy gap is examined as a function of substituent and the stabilisation energies of the singlet carbenes are compared with those of the isoelectronic carbocations H2CX+. Proton affinities are reported for the singlet carbenes and are compared with the proton affinities of similarly substituted ethylenes, H2C=CHX.

Diarylethenes with a Narrow Singlet-Triplet Energy Gap Sensitizer: a Simple Strategy for Efficient Visible-Light Photochromism

2018 ◽  
Vol 6 (6) ◽  
pp. 1700847 ◽  
Author(s):  
Zhiwei Zhang ◽  
Junji Zhang ◽  
Bin Wu ◽  
Xin Li ◽  
Yi Chen ◽  
...  
Keyword(s):  
Visible Light ◽  
Energy Gap ◽  
Triplet Energy ◽  
Simple Strategy
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