scholarly journals Thermalization in different phases of charged SYK model

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Tousik Samui ◽  
Nilakash Sorokhaibam
Keyword(s):  
Gas Phase ◽  
Effective Temperature ◽  
Liquid State ◽  
Chemical Potential ◽  
Final Value ◽  
Random Mass ◽  
Dilute Gas ◽  
Long Time ◽  
Spectral Statistics ◽  
Mass Deformation

Abstract We study thermalization of charged SYK model in two different phases. We show that both the highly chaotic liquid phase and the dilute gas phase thermalize. Surprisingly the dilute gas state thermalizes instantaneously. We argue that this phenomenon arises because the system in this phase consists of only long-lived quasi-particles at very low density. The liquid state thermalizes exponentially fast. We also show that the additional introduction of random mass deformation (q = 2 SYK term) slows down thermalization but the system thermalizes exponentially fast. This is observed despite the fact that the addition of large q = 2 SYK interaction forces spectral statistics to obey Poisson statistics. An interesting new observation is that the effective temperature is non-monotonic during thermalization in the liquid state. It has a bump at relatively long time before settling down to the final value. With non-zero chemical potential, the effective temperature oscillates noticeably before settling down to the final value.

scholarly journals Kinetically Trapped Liquid-State Conformers of a Sodiated Model Peptide Observed in the Gas Phase

2017 ◽  
Vol 121 (36) ◽  
pp. 6838-6844 ◽  
Author(s):  
Markus Schneider ◽  
Chiara Masellis ◽  
Thomas Rizzo ◽  
Carsten Baldauf
Keyword(s):  
Gas Phase ◽  
Liquid State ◽  
Model Peptide

Cationic and neutral nitrosamide: viable molecules in the dilute gas phase

1992 ◽  
Vol 199 (6) ◽  
pp. 643-647 ◽  
Author(s):  
Helge Egsgaard ◽  
Lars Carlsen ◽  
Thomas Weiske ◽  
Detlev Sülzle ◽  
Helmut Schwarz
Keyword(s):  
Gas Phase ◽  
Dilute Gas

scholarly journals Effects of Solvent Polarity on Solvation Free Energy, Dipole Moment, Polarizability, Hyperpolarizability and Molecular Properties of Metronidazole

2016 ◽  
Vol 19 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Mohammad Firoz Khan ◽  
Ridwan Bin Rashid ◽  
Md Yeunus Mian ◽  
Mohammad S Rahman ◽  
Mohammad A Rashid
Keyword(s):  
Free Energy ◽  
Dipole Moment ◽  
Gas Phase ◽  
Chemical Potential ◽  
Solvent Polarity ◽  
Solvation Free Energy ◽  
Molecular Properties ◽  
Chemical Hardness ◽  
Electrophilicity Index ◽  
Polar Solvents

A computational study of medium effect on solvation free energy, dipole moment, polarizability, hyperpolarizability and different molecular properties like chemical hardness & softness, chemical potential, electronegativity and electrophilicity index of metronidazole have been reported in this paper. Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level of theory with 6-31G (d,p) basis set was applied for gas phase and solution. The effect of solvent polarity on solvation free energy, dipole moment, polarizability, hyperpolarizability and molecular properties were calculated by employing Solvation Model on Density (SMD). The solvation free energies and dipole moment of metronidazole were found to be increased in nonpolar to polar solvents. The dipole moment of metronidazole was higher in different solvent than that of the gas phase. Moreover, from non-polar to polar solvents the chemical potential, electronegativity and electrophilicity index were increased. On the other hand, opposite relation was found in the case of chemical hardness and softness. The results obtained in this study may lead to understand the stability and reactivity of metronidazole and the results will be of assistance to use the title molecule as reaction intermediates and pharmaceuticals.Bangladesh Pharmaceutical Journal 19(1): 9-14, 2016

scholarly journals Electron-Induced Chemistry in the Condensed Phase

Atoms ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 33
Author(s):  
Jan Hendrik Bredehöft
Keyword(s):  
Gas Phase ◽  
Cross Sections ◽  
Condensed Phase ◽  
Theoretical Understanding ◽  
The Past ◽  
Long Time ◽  
The Difference ◽  
Molecule Interactions ◽  
Multi Body ◽  
Molecule Interaction

Electron–molecule interactions have been studied for a long time. Most of these studies have in the past been limited to the gas phase. In the condensed-phase processes that have recently attracted attention from academia as well as industry, a theoretical understanding is mostly based on electron–molecule interaction data from these gas phase experiments. When transferring this knowledge to condensed-phase problems, where number densities are much higher and multi-body interactions are common, care must be taken to critically interpret data, in the light of this chemical environment. The paper presented here highlights three typical challenges, namely the shift of ionization energies, the difference in absolute cross-sections and branching ratios, and the occurrence of multi-body processes that can stabilize otherwise unstable intermediates. Examples from recent research in astrochemistry, where radiation driven chemistry is imminently important are used to illustrate these challenges.

scholarly journals Synthesis, Characterization, Catalytic Activity, and DFT Calculations of Zn(II) Hydrazone Complexes

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4043 ◽  
Author(s):  
Temiloluwa T. Adejumo ◽  
Nikolaos V. Tzouras ◽  
Leandros P. Zorba ◽  
Dušanka Radanović ◽  
Andrej Pevec ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Molecular Orbital ◽  
Density Functional ◽  
Chemical Potential ◽  
Chemical Reactivity ◽  
Geometry Optimization ◽  
Coupling Reaction ◽  
Functional Theory ◽  
Reactivity Descriptors

Two new Zn(II) complexes with tridentate hydrazone-based ligands (condensation products of 2-acetylthiazole) were synthesized and characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy and single crystal X-ray diffraction methods. The complexes 1, 2 and recently synthesized [ZnL3(NCS)2] (L3 = (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium) complex 3 were tested as potential catalysts for the ketone-amine-alkyne (KA2) coupling reaction. The gas-phase geometry optimization of newly synthesized and characterized Zn(II) complexes has been computed at the density functional theory (DFT)/B3LYP/6–31G level of theory, while the highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO and LUMO) energies were calculated within the time-dependent density functional theory (TD-DFT) at B3LYP/6-31G and B3LYP/6-311G(d,p) levels of theory. From the energies of frontier molecular orbitals (HOMO–LUMO), the reactivity descriptors, such as chemical potential (μ), hardness (η), softness (S), electronegativity (χ) and electrophilicity index (ω) have been calculated. The energetic behavior of the investigated compounds (1 and 2) has been examined in gas phase and solvent media using the polarizable continuum model. For comparison reasons, the same calculations have been performed for recently synthesized [ZnL3(NCS)2] complex 3. DFT results show that compound 1 has the smaller frontier orbital gap so, it is more polarizable and is associated with a higher chemical reactivity, low kinetic stability and is termed as soft molecule.

scholarly journals Analysis of the Gas Phase Acidity of Substituted Benzoic Acids Using Density Functional Concepts

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1631
Author(s):  
Jorge A. Amador-Balderas ◽  
Michael-Adán Martínez-Sánchez ◽  
Ramsés E. Ramírez ◽  
Francisco Méndez ◽  
Francisco J. Meléndez
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Chemical Potential ◽  
Fukui Function ◽  
Ortho Position ◽  
Benzoic Acids ◽  
Functional Theory ◽  
Resonance Effects ◽  
Gas Phase Acidity ◽  
Substituted Benzoic Acids

A theoretical study of the effect of the substituent Z on the gas phase acidity of substituted benzoic acids ZC6H4COOH in terms of density functional theory descriptors (chemical potential, softness and Fukui function) is presented. The calculated gas phase ΔacidG° values obtained were close to the experimental ones reported in the literature. The good relationship between the ΔacidG° values and the electronegativity of ZC6H4COOH and its fragments, suggested a better importance of the inductive than polarizability contributions. The balance of inductive and resonance contributions of the substituent in the acidity of substituted benzoic acids showed that the highest inductive and resonance effects were for the -SO2CF3 and -NH2 substituents in the para- and ortho-position, respectively. The Fukui function confirmed that the electron-releasing substituent attached to the phenyl ring of benzoic acid decreased the acidity in the trend ortho > meta > para, and the electron-withdrawing substituent increased the acidity in the trend ortho < meta < para.

scholarly journals White Dwarf Pulsations

1980 ◽  
Vol 5 ◽  
pp. 469-472
Author(s):  
W. Dziembowski
Keyword(s):  
Effective Temperature ◽  
High Speed ◽  
White Dwarfs ◽  
Binary Systems ◽  
Early Suggestion ◽  
Nonradial Oscillation ◽  
High Speed Photometry ◽  
Long Time ◽  
Nuclear Burning ◽  
Radial Pulsations

It has been known for a long time that white dwarfs are pulsationally unstable if nuclear burning takes place in their envelopes. Perturbation of energy generation rate promotes pulsational instability and this effect is frequently referred to as ε-mechanism. In recent years, with the advent of high-speed photometry, many rapidly varying white dwarfs have been discovered. However, periods of variability were found to be significantly longer than the periods of radial pulsations which were the only type of oscillations considered before the discovery. Furthermore, the case of ε-mechanism as being responsible for the observed variability has never been made strong for any of the observed objects.Variable white dwarfs are found among: Io single DA-type objects in the effective temperature range 10000-15000K; 2o members of close, usually but not always, cataclysmic binary systems. Although, following an early suggestion by Warner and Robinson (1972), the excitation of nonradial oscillation is postulated in both cases, the two types represent very different physical situations and they will be discussed here separately.

Pt(111) reconstruction induced by enhanced Pt gas-phase chemical potential

1993 ◽  
Vol 70 (10) ◽  
pp. 1489-1492 ◽  
Author(s):  
Michael Bott ◽  
Michael Hohage ◽  
Thomas Michely ◽  
George Comsa
Keyword(s):  
Gas Phase ◽  
Chemical Potential ◽  
Phase Chemical

Topological phase transition in effective model of QCD with chiral nonrestoration

2015 ◽  
Vol 24 (03) ◽  
pp. 1550021
Author(s):  
Tran Huu Phat ◽  
Nguyen Tuan Anh ◽  
Phung Thi Thu Ha
Keyword(s):  
Phase Transition ◽  
Liquid State ◽  
Chemical Potential ◽  
Equations Of State ◽  
Effective Model ◽  
Topological Phase ◽  
Baryon Chemical Potential ◽  
Fermi Sphere ◽  
Topological Phase Transition ◽  
First Order Transition

The topological phase transition is studied systematically within an effective model of Quantum Chromodynamics (QCD) where the chiral symmetry, broken at zero temperature, is not restored at high temperature and/or baryon chemical potential. It is found that during phase transition the system undergoes a first-order transition from the nonFermi liquid state to the Fermi liquid state which is protected by topology of the Fermi sphere. The phase diagram of the transition in the plane of temperature and baryon chemical potential is established. The critical behaviors of various equations of state are determined.

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