Stability line of liquid molecular nitrogen based on the SCAN meta- GGA density functional

2018 ◽  
Vol 98 (18) ◽  
Author(s):  
G. Zhao ◽  
H. Wang ◽  
M. C. Ding ◽  
X. G. Zhao ◽  
H. Y. Wang ◽  
...  
Keyword(s):  
Density Functional ◽  
Molecular Nitrogen ◽  
Stability Line

scholarly journals Syntone Chemistry. Theoretical study on the formation of glycine, alannine and serine

2019 ◽  
Vol 70 (5) ◽  
pp. 1707-1711
Author(s):  
Gheorghe Surpateanu ◽  
Ileana Denisa Nistor ◽  
Ana-Maria Georgescu ◽  
Neculai Catalin Lungu
Keyword(s):  
Amino Acids ◽  
Density Functional ◽  
Molecular Nitrogen ◽  
Density Functional Method ◽  
Functional Method ◽  
Enthalpies Of Formation ◽  
Free Energies ◽  
Formation Reaction ◽  
Quantitative Results ◽  
Reactivity Study

Three synthons: methylene, nitrene and carbon monoxide form aziridinone in the presence of molecular nitrogen at low temperatures. This one, in contact with the same three synthons could form the precursors of the first proteinogenic amino acids. This paper is a theoretical, thermodynamically and reactivity study concerning the formation of the three previously named amino acids at low temperature conditions. The key intermediates are identified in the formation of the three amino acids: aziridinone, aziridinonil and methyl-aziridinonil radicals. The quantitative results, enthalpies of formation, reaction enthalpies and free energies were taken from quantum mechanical calculations acquired by density functional method (DFT): B88-LYP.

scholarly journals Role of Chemical Structure of Support in Enhancing the Catalytic Activity of a Single Atom Catalyst Toward NRR: A Computational Study

2021 ◽  
Vol 9 ◽  
Author(s):  
Thillai Govindaraja Senthamaraikannan ◽  
Selvaraj Kaliaperumal ◽  
Sailaja Krishnamurty
Keyword(s):  
Metal Atom ◽  
Density Functional ◽  
Computational Study ◽  
Molecular Nitrogen ◽  
Red Shift ◽  
Single Atom ◽  
Metal Atoms ◽  
Doped Graphene ◽  
Adsorption Energies

Using the periodic density functional theory–based methodology, we propose a potential catalytic system for dinitrogen activation, viz., single metal atoms (Mo, Fe, and V) supported on graphene-based sheets. Graphene-based sheets show an excellent potential toward the anchoring of single atoms on them (Mo, Fe, and V) with adsorption energies ranging between 1.048 and 10.893 eV. Factors such as defects and BN doping are noted to enhance the adsorption energies of single metal atoms on the support. The adsorption of a dinitrogen molecule on metal atom–anchored graphene-based supports is seen to be highly favorable, ranging between 0.620 and 2.278 eV. The adsorption is driven through a direct hybridization between the d orbitals of the metal atom (Mo, Fe, and V) on the support and the p orbital of the molecular nitrogen. Noticeably, BN-doped graphene supporting a single metal atom (Mo, Fe, and V) activates the N2 molecule with a red shift in the N–N stretching frequency (1,597 cm−1 as compared to 2,330 cm−1 in the free N2 molecule). This red shift is corroborated by an increase in the N–N bond length (1.23 Å from 1.09 Å) and charge transfer to an N2 molecule from the catalyst.

Density functional theory calculations of molecular nitrogen on a ruthenium cluster

1999 ◽  
Vol 313 (1-2) ◽  
pp. 279-282 ◽  
Author(s):  
Keshav N Shrivastava ◽  
S.S.C Ammal ◽  
H Tsuruya ◽  
S Takami ◽  
A Endou ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Molecular Nitrogen ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Ruthenium Cluster

scholarly journals Neural Network Sampling of the Free Energy Landscape for Nitrogen Dissociation on Ruthenium

2021 ◽  
Author(s):  
Elizabeth Lee ◽  
Thomas Ludwig ◽  
Boyuan Yu ◽  
Aayush Singh ◽  
François Gygi ◽  
...  
Keyword(s):  
Free Energy ◽  
Heterogeneous Catalysis ◽  
Density Functional ◽  
Energy Surface ◽  
Molecular Nitrogen ◽  
Harmonic Approximation ◽  
Molecular State ◽  
Transition Metal Catalysts ◽  
Vibrational Entropy ◽  
Free Energy Surface

<p>In heterogeneous catalysis, free energy profiles of reactions govern the mechanisms, rates, and equilibria. Energetics are conventionally computed using the harmonic approximation (HA), which requires determination of critical states <i>a priori</i>. Here, we use neural networks to efficiently sample and directly calculate the free energy surface (FES) of a prototypical heterogeneous catalysis reaction—the dissociation of molecular nitrogen on ruthenium—at density functional theory-level accuracy. We find vibrational entropy of surface atoms, often neglected in HA for transition metal catalysts, contributes significantly to the reaction barrier. The minimum free energy path for dissociation reveals an “on-top” adsorbed molecular state prior to the transition state. While a previously reported flat-lying molecular metastable state can be identified in the potential energy surface, it is absent in the FES at relevant reaction temperatures. These findings demonstrate the importance of identifying critical points self-consistently on the FES for reactions that involve considerable entropic effects.</p>

Doping effects on the geometric and electronic structure of tin clusters

2019 ◽  
Vol 21 (44) ◽  
pp. 24478-24488 ◽  
Author(s):  
Martin Gleditzsch ◽  
Marc Jäger ◽  
Lukáš F. Pašteka ◽  
Armin Shayeghi ◽  
Rolf Schäfer
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Beam Deflection ◽  
Functional Theory ◽  
Doping Effects ◽  
Depth Analysis ◽  
Trajectory Simulations

In depth analysis of doping effects on the geometric and electronic structure of tin clusters via electric beam deflection, numerical trajectory simulations and density functional theory.

What correlation effects are covered by density functional theory?

2000 ◽  
Vol 98 (20) ◽  
pp. 1639-1658 ◽  
Author(s):  
Yuan He, Jurgen Grafenstein, Elfi Kraka,
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Correlation Effects ◽  
Functional Theory

Accurate density functional thermochemistry for larger molecules

1997 ◽  
Vol 91 (3) ◽  
pp. 555-559 ◽  
Author(s):  
KRISHNAN RAGHAVACHARI ◽  
BORIS STEFANOV ◽  
LARRY CURTISS
Keyword(s):  
Density Functional
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