scholarly journals The rotation–vibration spectrum of methyl fluoride from first principles

2019 ◽  
Vol 21 (7) ◽  
pp. 3496-3505 ◽  
Author(s):  
Alec Owens ◽  
Andrey Yachmenev ◽  
Jochen Küpper ◽  
Sergei N. Yurchenko ◽  
Walter Thiel
Keyword(s):  
First Principles ◽  
Vibration Spectrum ◽  
State Of The Art ◽  
Methyl Fluoride ◽  
Theoretical Methods

State-of-the-art theoretical methods are used to investigate the rotation–vibration spectrum of methyl fluoride.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

Interface Electronic And Magnetic Structures Of Layered Fe In Contact With MgO

1991 ◽  
Vol 238 ◽  
Author(s):  
Young Keun Kim ◽  
Michael E. McHenry ◽  
Manuel P. Oliveria ◽  
Mark E. Eberhart
Keyword(s):  
First Principles ◽  
State Of The Art ◽  
Magnetic Moments ◽  
Magnetic Structures ◽  
Consistent Field ◽  
Structure Of Metal ◽  
Metal Ceramic ◽  
Layer Technique ◽  
Self Consistent Field ◽  
Ceramic Interfaces

ABSTRACTA model based on the state-of-the-art, first-principles layer Korringa-Kohn-Rostoker (LKKR) method has proven to be very effective in describing the electronic and magnetic structure of metal/ceramic interfaces. We have performed self-consistent field computations incorporating spin polarization both for Fe/MgO superlattice (bulk technique) and for MgO/Fe/MgO sandwich (layer technique) systems. Muffin-tin potentials were employed for both materials in our computations. Iron layer was embedded in MgO, the host material, to have a [110](100)Fe / [100](100)MgO contact configuration. A large enhancement of magnetic moments has been found at the interface.

First-Principles Investigations of Hydrogen and Fluorine on Silicon Surfaces

1992 ◽  
Vol 259 ◽  
Author(s):  
Chris G. Van De Walle
Keyword(s):  
First Principles ◽  
Etch Rate ◽  
State Of The Art ◽  
Interstitial Impurity ◽  
Silicon Surfaces ◽  
Hydrogen Solubility ◽  
First Principles Calculations ◽  
Energy Diagram

ABSTRACTState-of-the-art first-principles calculations allow detailed studies of the mechanisms by which hydrogen and fluorine interact with silicon. The results for hydrogen are presented in the form of an energy diagram which includes many different configurations. The theoretical values allow a discussion of issues such as hydrogen solubility, and desorption from a Si surface. For fluorine, we investigate the behavior as an interstitial impurity in the bulk, as well as Si-F interactions at or near the surface. A study of the insertion of F atoms into Si-Si bonds elucidates the microscopic mechanisms of etching, and the dependence of etch rate on doping. Thermodynamic aspects of HF etching are briefly discussed.

Atomic Structure of CaSi2/Si Interfaces

1989 ◽  
Vol 159 ◽  
Author(s):  
Chris G. Van De Walle
Keyword(s):  
Schottky Barrier ◽  
Atomic Structure ◽  
First Principles ◽  
State Of The Art ◽  
Interfacial Structure ◽  
First Principles Calculations ◽  
Barrier Heights

ABSTRACTThe CaSi2/Si interface is studied with state-of-the-art first-principles calculations. Various models for the interfacial structure are examined, in which the Ca atoms at the interface exhibit 5-, 6-, 7-, or 8-fold coordination. The structures with sevenfold coordination (as in bulk CaSi2) have the lowest energy. However, the sixfold- and eightfold-coordinated structures are only ∼0.1 eV higher in energy. Schottky barrier heights are briefly discussed.

Theoretical Strength of Metals and Intermetallics from First Principles

2005 ◽  
Vol 482 ◽  
pp. 33-38 ◽  
Author(s):  
Mojmír Šob ◽  
Jaroslav Pokluda ◽  
Miroslav Černý ◽  
Pavel Šandera ◽  
V. Vitek
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
First Principles ◽  
State Of The Art ◽  
The State ◽  
Experimental Results ◽  
Theoretical Strength ◽  
Stability Conditions ◽  
The Stability

The state of the art of ab-initio calculations of the theoretical strength (TS) of materials is summarized and a database of selected theoretical and experimental results presented. Differences between theoretical and experimental TS values are discussed by assessing the stability conditions.

scholarly journals SARS-CoV2 Variants and Vaccines mRNA Spikes Fibonacci Numerical UA/CG Metastructures

2021 ◽  
Author(s):  
Jean-Claude Perez
Keyword(s):  
Mrna Stability ◽  
State Of The Art ◽  
Fibonacci Numbers ◽  
Standing Waves ◽  
Protein Sequences ◽  
Theoretical Methods ◽  
Synonymous Codons ◽  
The World ◽  
One Year ◽  
Almost All

In this paper, we suggest a biomathematical numerical method analysing mRNA nucleotides sequences based on UA/CG Fibonacci numbers proportions. This method is used to evaluate then compare the spike genes related to the main SARS-CoV2 VARIANTS circulating presently within the world. The 9 main results proposed to be reproduced by peers are: 1/ SARS-CoV2 genome and spike evolution in one year 2020-2021. 2/ SARS-CoV2 Origins. 3/ Comparing 11 reference variants spikes. 4/ analysing 32 CAL.20C california variant patients spikes. 5/ Toward a meta mRNA Fibonacci gene end message code. 6/ analysing S501 UK, S484 South Afrika and &laquo; 2 mutations &raquo; IINDIA variants. 7/ Suggesting a possible variants spike mRNA palindrome symmetry metastructure improving mRNA stability then infectuosity. 8/ Analysing Fibonacci Metastructures in the mRNA coding for the vaccines PFIZER and MODERNA. 9/ Does the CG-rich modification of the synonymous codons of the spikes of the 2 mRNA vaccines affect the expression and quantity of SARS-CoV2 antibodies? Particularly, we suggest the following conjecture at mRNA folding level : CONJECTURE of SARS-CoV2 VARIANTS: The growth of long Fibonacci structures in the shape of "podiums" for almost all of the variants studied (UK, California, South Afrika, India, etc.) suggests the probable folding of the Spike mRNA in the form of a "hairpin", which can strengthen the cohesion and the lifespan of this mRNA. Finally, we show that this kind of Fibonacci matastructures disapears TOTALLY analysing the published mRNA sequences of PFIZER and MODERNA vaccines. One fact is certain, the 2 mRNAs of the Moderna and Pfizer vaccines will result in a low functionality of the spike vaccine because by doping these sequences in CG rich, their designers, in search of greater STABILITY of these RNAs will have built, according to us , sequences which, as soon as they are inserted into the human host, will seek to mutate, like SARS-CoV2 variants, towards CG ==&gt; UA forms in order to improve, paradoxically, their STABILITY and probably also their LIFETIME.. Particularly, using new biomathematics theoretical methods (Master code and numerical standing waves), and comparing the Spikes of the 2 vaccines Moderna and Phizer, we conclude a very probable difference in stability and shelf life of the 2 respective mRNAs of these 2 vaccines. However, the &ldquo;State of the Art&rdquo; will tell you that their 2 protein sequences are strictly identical. However, by having modified their synonymous codons using different strategies, no one can guarantee that the quantity of antibodies generated will be identical in the 2 cases.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

Sign in / Sign up

Export Citation Format

Share Document