Quantum mechanics

In this review we probe the reaction mechanisms for formation of DNA nucleobases from formamide (FM) following the free radical pathways that have been identified by quantum chemical computations. Formamide is known as a precursor of nucleobases in the prebiotic chemistry of the Early Earth or in the nitrogen-rich atmosphere such as Titan, regardless of whether water is present or absent.

34p viyoko 01-10-2024 3 1   Download

The limits of current micro-scale technology is approaching rapidly. As the technology is going toward nano-scale devices, physical phenomena involved are fundamentally different from micro-scale ones. Principles in classical physics are no longer powerful enough to explicate the phenomena involved in nano-scale devices. At this stage, quantum mechanic sheds some light on those topics which cannot be described by classical physics. The primary focus of this research work is the development of an analysis technique for understanding the behavior of strongly perturbed harmonic oscillators.

165p runthenight07 01-03-2023 6 3   Download

This research is built upon the determination of the Eigenpairs of one and two dimensional positive differential operators with periodic boundary conditions. The Schrödinger equation was solved for positive operators in both one and two dimensions. Fourier series were used to express the derivatives as the summation of Fourier terms. This led to a novel approach for the calculation of the eigenmodels of a perturbed potential well. The perturbation can be done via an electric field applied to the potential well.

88p runthenight07 01-03-2023 6 3   Download

Lecture Physics A2: Fundamental of Quantum Mechanics - PhD. Pham Tan Thi present the content diffraction of light/electron by one slit, double-slits experiments for electrons, wave-particle duality, De Broglie’s hypothesis, for a non-relativistic free particle,...

41p xusong 21-07-2021 31 2   Download

Lecture Physics A2: Atomic physics - PhD. Pham Tan Thi present the content history of atomic model, quantum mechanical atomic theory, Schrödinger Equation in three dimensions, particle in a three-dimensional box, energy degeneracy,...

39p xusong 21-07-2021 31 2   Download

Due to helical cylindrical time-evolution of electrons the mankind observation at a quantum mechanical scale depends on synchronization between observers and their surrounding cosmological medium by collective dynamics. From one side, the synchronization leads to linearization of an embedded 4D space-time reminiscent of the flat Minkowski space-time.

7p tamynhan6 14-09-2020 10 1   Download

In this work, we investigated the adsorption mechanism of acetone and toluene on the surface of silicene by the quantum simulation method. The images of the potential energy surfaces for different positions of the adsorbate on the silicene surface were explored by Computational DFTbased Nanoscope tool for determination of the most stable configurations and diffusion possibilities.

8p tamynhan6 14-09-2020 24 3   Download

DFT calculations indicate that the decomposition reaction of nitroethyl benzoates in the presence of 1,3-dimethylimidazolium cation takes place much faster than in the case of the non-catalyzed process. Additionally, our calculations suggest one-step polar mechanism of title reactions.

8p tocectocec 25-05-2020 13 1   Download

The quantum-chemical modeling mechanism of the [4+2]-cycloaddition reaction of 2,3 dimethylbuta-1,3-diene and methyl acrylate was conducted. Its qualitative aspects were analyzed at the molecular level by the program MOPAC2012 and semiempirical method RM1.

6p tocectocec 25-05-2020 7 1   Download

The mechanism of corrosion inhibition was explored and supplemented by adsorption and surface morphological studies. Quantum mechanical investigations on corrosion behaviour of compounds were also conducted and satisfying correlation was noticed between the results of corrosion measurement methods and quantum mechanical evaluations.

12p tocectocec 25-05-2020 19 2   Download

The corrosion inhibition efficiencies of two novel Schiff bases, namely (E)-3-[thiophen-2-lmethyleneamino]benzoic acid (T2YMABA) and (E)-4-(5-[(2-phenylhydrazono) methyl]thiophen-2-yl)benzoic acid (PHMT2YBA) on mild steel (MS) in 1.0M HCl solution has been investigated and compared using electrochemical impedance spectroscopy and potentiodynamic polarization analysis.

10p tocectocec 25-05-2020 19 2   Download

In present work, the formation constants, logb110, logb120 and the concentration of [M] and [MLi ] in complex solutions of Cu2+ and the amino acids were determined by using the quantitative electron structure and properties relationships (QESPRs) and quantitative complex and complex relationships (QCCRs). The relative charge nets for complex structures were calculated by using molecular mechanics MM+ and semiempirical quantum chemistry calculations ZINDO/1. The QESPRs and QCCRs models were constructed by the atomic charge net on complex structures and the multivariate regression analysis.

8p kethamoi1 20-11-2019 27 2   Download

Quantum Mechanics and the Hydrogen Atom, Many-Electron Atoms and Chemical Bonding, Molecular Orbitals, Spectroscopy, and Chemical Bonding,... as the main contents of the lesson lecture 9 "Tentative material to be covered for Exam 2". Invite you to consult the lesson for more documents serving the academic needs and research.

38p nguyenphong201 11-12-2015 35 2   Download

The photocatalytic oxidation of reactive blue 2 and reactive red 120 has been studied by using TiO2 Degussa P25 as catalyst and UV-light. The formation of intermediate molecules could be predicted on the basic of point charge calculations on all the individual atoms of the dyes. The agreement between calculations from quantum theory and the results of experiments was the background to establish a pathway for degradation of reactive dyes. A plausible mechanism of dye photodegradations is discussed.

6p uocvong03 24-09-2015 87 3   Download

In the present article, we address the question that how important role do the Quantum Mechanic (QM) and Molecular Mechanics (MM) forces play in ligand docking on protein, via the use semi-quantum relaxation approach (SQRA) using different forces, e.g. quantum, Van der Waals and Coulomb ones, in the process of ligand - protein docking. The QM approximation is applied to calculate the QM forces of neighbor protein-atoms acting on ligands. The L-J 6-12 empirical potential model and Coulomb rule are applied to calculate the forces from the rest protein-atoms on each ligand - atom.

11p uocvong01 24-09-2015 62 4   Download

Recent years have witnessed high levels of activity in identifying enzyme systems that catalyse H-transfer by quantum tunneling. Rather than being restricted to a small number of specific enzymes as perceived initially, it has now become an accepted mechanism for H-transfer in a growing number of enzymes. Furthermore, H-tunneling is driven by the thermally induced dynamics of the enzyme. In some of those enzymes that break stable C–H bonds the reaction proceeds purely by quantum tunneling, without the need to partially ascend the barrier.

7p system191 01-06-2013 40 3   Download

Kinetic experiments with a substrate series of phenylacetyl-arylamides reveal that at least one polar group in the amine moiety is required for the proper orientation of the substrate in the large nucleophile-binding subsite of penicillin acylase ofEscherichia coli. Quantum mechanical molecular model-ling of enzyme–substrate interactions in the enzyme active site shows that in the case of substrates lacking local sym-metry, the productive binding implies two nonsymmetrical arrangements with respect to the two positively charged guanidinium residues of ArgA145 and ArgB263....

8p dell39 03-04-2013 43 3   Download

At least half of all enzyme-catalysed reactions are thought to involve a hydrogen transfer. In the last 10 years, it has become apparent that many of these reactions will occur, in part, or in full, by quantum mechanical tunnelling. We are particularly interested in the role of promoting vibra-tions on H transfer, and the Old Yellow Enzyme family of flavoproteins has proven to be an excellent model system with which to examine such reactions.

12p vinaphone15 25-02-2013 25 4   Download

Molecular dynamics simulations employing a combined quantum mechani-cal and molecular mechanical potential have been carried out to elucidate the reaction mechanism of the hydrolysis of a cyclic nucleotide cAMP sub-strate by phosphodiesterase 4B (PDE4B).

17p cosis54 05-01-2013 44 4   Download

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Dynamics and mechanisms of quantum dot nanoparticle cellular uptake

9p toshiba25 08-12-2011 50 5   Download