Out-of-plane deformation pathways of the R(X=)C-NR2 fragment present in amides, thioamides, amidines, enamines, and anilines. A concerted study making use of structural data, molecular mechanics, and ab initio calculations

1993 ◽  
Vol 97 (51) ◽  
pp. 13568-13574 ◽  
Author(s):  
Valeria Ferretti ◽  
Valerio Bertolasi ◽  
Paola Gilli ◽  
Gastone Gilli
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Molecular Mechanics ◽  
Plane Deformation ◽  
Structural Data ◽  
Out Of Plane

Configurational Assignment and Conformational Study of Methylglyoxal Bisdimethylhydrazones Derived from the 2-Ethoxypropenal Precursor

2006 ◽  
Vol 59 (3) ◽  
pp. 211 ◽  
Author(s):  
Leonid B. Krivdin ◽  
Lyudmila I. Larina ◽  
Kirill A. Chernyshev ◽  
Natalia A. Keiko
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Experimental Measurements ◽  
Conformational Study ◽  
Lone Pairs ◽  
Configurational Assignment ◽  
Out Of Plane ◽  
High Level

A configurational assignment of the isomeric methylglyoxal bisdimethylhydrazones derived from the 2-ethoxypropenal precursor has been performed based on experimental measurements and high-level ab initio calculations of 1J(C,C) and 1J(C,H) couplings. The results reveal the marked stereochemical dependence upon the orientation of the lone pairs of both nitrogen atoms in different isomers. Methylglyoxal bisdimethylhydrazone is shown to exist in a mixture of the EE and ZE isomers (ca. 75:25), both of which adopt predominant s-trans conformations with minor (up to 8°) out-of-plane deviations.

Hydration ofcis andtrans N-methylformamide as revealed by the use of17O-NMR, molecular mechanics, and ab initio calculations

Biopolymers ◽  
1995 ◽  
Vol 36 (4) ◽  
pp. 415-428 ◽  
Author(s):  
Ioannis P. Gerothanassis ◽  
Ioannis N. Demetropoulos ◽  
Constantina Vakka
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Molecular Mechanics

scholarly journals Out-of-plane emission of trions in monolayer WSe2 revealed by whispering gallery modes of dielectric microresonators

2020 ◽  
Author(s):  
Daniel Andres-Penares ◽  
Mojtaba Karimi Hábil ◽  
Alejandro Molina-Sánchez ◽  
Carlos Zapata-Rodríguez ◽  
Juan Martinez-Pastor ◽  
...  
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Close Contact ◽  
Spectroscopic Method ◽  
Whispering Gallery Modes ◽  
Quantum Communications ◽  
Whispering Gallery ◽  
Plane Component ◽  
Out Of Plane ◽  
On Chip

Abstract The manipulation of light emitted by two-dimensional semiconductors grounds forthcoming technologies in the field of on-chip communications. However, these technologies require from the so elusive out-of-plane photon sources to achieve an efficient coupling of radiated light into planar devices. Here we propose a versatile spectroscopic method that enables the identification of the out-of-plane component of dipoles due to the selective coupling of light emitted by in-plane and out-of-plane dipoles to the whispering gallery modes of spherical dielectric microresonators, in close contact to them. We have applied this method to demonstrate the existence of dipoles with an out-of-plane orientation in monolayer WSe2 at room temperature, by means of micro-photoluminescent measurements, numerical simulations based on finite element methods, and ab-initio calculations. Experimental results and ab-initio calculations identify trions as the source responsible for this out-of-plane emission, opening new routes for realizing on-chip integrated systems with applications in information processing and quantum communications.

scholarly journals Dynamics Studies of Nitrogen Interstitial in GaN from Ab Initio Calculations

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3627
Author(s):  
Huan He ◽  
Wenbo Liu ◽  
Pengbo Zhang ◽  
Wenlong Liao ◽  
Dayin Tong ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Separation Distance ◽  
Semiconductor Materials ◽  
Stable Configuration ◽  
Anisotropic Behavior ◽  
Out Of Plane ◽  
First Time ◽  
Good Agreement

Understanding the properties of defects is crucial to design higher performance semiconductor materials because they influence the electronic and optical properties significantly. Using ab initio calculations, the dynamics properties of nitrogen interstitial in GaN material, including the configuration, migration, and interaction with vacancy were systematically investigated in the present work. By introducing different sites of foreign nitrogen atom, the most stable configuration of nitrogen interstitial was calculated to show a threefold symmetry in each layer and different charge states were characterized, respectively. In the researches of migration, two migration paths, in-plane and out-of-plane, were considered. With regards to the in-plane migration, an intermediated rotation process was observed first time. Due to this rotation behavior, two different barriers were demonstrated to reveal that the migration is an anisotropic behavior. Additionally, charged nitrogen Frenkel pair was found to be a relatively stable defect complex and its well separation distance was about 3.9 Å. Part of our results are in good agreement with the experimental results, and our work provides underlying insights of the identification and dynamics of nitrogen interstitial in GaN material. This study of defects in GaN material is useful to establish a more complete theory and improve the performance of GaN-based devices.

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