Vibrational Analysis of Paraelectric–Ferroelectric Transition of LiNbO3: An Ab-Initio Quantum Mechanical Treatment

The phase transitions between paraelectric (PE) and ferroelectric (FE) isomorph phases of LiNbO3 have been investigated quantum mechanically by using a Gaussian-type basis set, the B3LYP hybrid functional and the CRYSTAL17 code. The structural, electronic and vibrational properties of the two phases are analyzed. The vibrational frequencies evaluated at the Γ point indicate that the paraelectric phase is unstable, with a complex saddle point with four negative eigenvalues. The energy scan of the A2u mode at −215 cm−1 (i215) shows a dumbbell potential with two symmetric minima. The isotopic substitution, performed on the Li and Nb atoms, allows interpretation of the nontrivial mechanism of the phase transition. The ferroelectric phase is more stable than the paraelectric one by 0.32 eV.

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Vibrational Analysis and Molecular Docking Studies on some Ribonuclease-H HIV Inhibitors

Biointerface Research in Applied Chemistry ◽

10.33263/briac115.1279612807 ◽

2021 ◽

Vol 11 (5) ◽

pp. 12796-12807

Keyword(s):

Human Immunodeficiency Virus ◽

Vibrational Analysis ◽

Docking Studies ◽

Rnase H ◽

Basis Set ◽

Ribonuclease H ◽

Hiv Reverse Transcriptase ◽

Hybrid Functional ◽

Immunodeficiency Virus ◽

And Performance

Ribonuclease-H (RNase-H) enzyme of the human immunodeficiency virus (HIV) reverse transcriptase (RT) shows inhibitory activity with novel galloyl derivatives having enzymatic assays of IC50 S at sub to low micromolar concentration. The computational analysis of these stated galloyl derivatives was carried out in order to extract information and performance with the target proteins. The compounds N-hydroxylisoquinolinediones (HID), β-thujaplicinol, diketoacid, diketoacid ester, pyrimidinol carboxylic acids, naphthyridinones, 3hydroxypyrimidine-2,4-dione (HPD), and hydroxypyridonecarboxylic acids are the selected galloyl derivatives of human immunodeficiency virus-I (HIV-I) RNase-H active site inhibitors that were optimized using Turbomole software. Further evaluation of their NMR shielding of the stated compounds was performed using B3-LYP hybrid functional, and the def-SV basis set was carried out from the same software. These optimized compounds were then docked to targets (PDB Id: 5EGA and 3K2P) using AutoDock 4 software. After analyzing the docking result, Hydroxylisoquinoline and Naphthyridinones give better binding results with both the targets.

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IMPLICATIONS OF A QUANTUM MECHANICAL TREATMENT OF THE UNIVERSE

Modern Physics Letters A ◽

10.1142/s0217732398000401 ◽

1998 ◽

Vol 13 (05) ◽

pp. 347-351 ◽

Cited By ~ 1

Author(s):

MURAT ÖZER

Keyword(s):

Quantum Mechanics ◽

Wave Packet ◽

Early Universe ◽

Mechanical Treatment ◽

Correspondence Principle ◽

Scale Factor ◽

Quantum Mechanical ◽

Quantum Mechanical Treatment ◽

The Standard Model ◽

The Universe

We attempt to treat the very early Universe according to quantum mechanics. Identifying the scale factor of the Universe with the width of the wave packet associated with it, we show that there cannot be an initial singularity and that the Universe expands. Invoking the correspondence principle, we obtain the scale factor of the Universe and demonstrate that the causality problem of the standard model is solved.

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