scholarly journals Quantifying how step-wise fluorination tunes local solute hydrophobicity, hydration shell thermodynamics and the quantum mechanical contributions of solute–water interactions

2020 ◽  
Vol 22 (40) ◽  
pp. 22997-23008
Author(s):  
João R. Robalo ◽  
Denilson Mendes de Oliveira ◽  
Petra Imhof ◽  
Dor Ben-Amotz ◽  
Ana Vila Verde
Keyword(s):  
Hydration Shell ◽  
Quantum Mechanical ◽  
Solute Water

Locally tuning solute–water interactions with fluorination.

scholarly journals Ab initio QM/MM MD simulations of the hydrated Ca2+ ion

2004 ◽  
Vol 76 (1) ◽  
pp. 37-47 ◽  
Author(s):  
C. F. Schwenk ◽  
B. M. Rode
Keyword(s):  
Density Functional ◽  
Hydration Shell ◽  
Md Simulations ◽  
Distribution Functions ◽  
Quantum Mechanical ◽  
Hartree Fock ◽  
Velocity Autocorrelation ◽  
Exchange Processes ◽  
Hydrate Complex ◽  
Dynamical Properties

The comparison of two different combined quantum mechanical (QM)/molecular mechanical (MM) simulations treating the quantum mechanical region at Hartree-Fock (HF) and B3-LYP density functional theory (DFT) level allowed us to determine structural and dynamical properties of the hydrated calcium ion. The structure is discussed in terms of radial distribution functions, coordination number distributions, and various angular distributions and the dynamical properties, as librations and vibrations, reorientational times and mean residence times were evaluated by means of velocity autocorrelation functions. The QM/MM molecular dynamics (MD) simulation results prove an eightfold-coordinated complex to be the dominant species, yielding average coordination numbers of 7.9 in the HF and 8.0 in the DFT case. Structural and dynamical results show higher rigidity of the hydrate complex using DFT. The high instability of calcium ion's hydration shell allows the observation of water-exchange processes between first and second hydration shell and shows that the mean lifetimes of water molecules in this first shell (<100 ps) have been strongly overestimated by conclusions from experimental data.

scholarly journals STRUCTURE OF IRIDIUM(III) HYDRATION BASED ON AB INITIO QUANTUM MECHANICAL CHARGE FIELD MOLECULAR DYNAMICS SIMULATIONS

2010 ◽  
Vol 10 (3) ◽  
pp. 352-356 ◽  
Author(s):  
Ponco Iswanto ◽  
Ria Armunanto ◽  
Harno D. Pranowo
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Complex Structure ◽  
Hydration Shell ◽  
Basis Sets ◽  
Quantum Mechanical ◽  
Ion Hydration ◽  
Charge Field ◽  
Mechanical Charge ◽  
First Hydration Shell

Structural properties of Iridium(III) hydration have been studied based on an ab initio Quantum Mechanical Charge Field (QMCF) Molecular Dynamics (MD) Simulations. The most chemical-relevant region was treated by ab initio calculation at Hartree-Fock level. For the remaining region was calculated by Molecular Mechanics method. LANL2DZ ECP and DZP Dunning basis sets were applied to Ir3+ ion and water, respectively. The average distance of Ir-O in the first hydration shell is 2.03 Å. The QMCF MD Simulation can detect only one complex structure with coordination number of 6 in the first hydration shell. Bond angle analysis shows that Ir3+ ion hydration in the first hydration shell has octahedral structure.

Operators and meaning of wave function

2016 ◽  
pp. 4039-4042
Author(s):  
Viliam Malcher
Keyword(s):  
Wave Function ◽  
Quantum Theory ◽  
State Vector ◽  
The State ◽  
Physical Significance ◽  
Central Problem ◽  
Quantum Mechanical ◽  
Mechanical Description ◽  
Quantum Mechanical Description ◽  
Interpretation Of Quantum Theory

The interpretation problems of quantum theory are considered. In the formalism of quantum theory the possible states of a system are described by a state vector. The state vector, which will be represented as |ψ> in Dirac notation, is the most general form of the quantum mechanical description. The central problem of the interpretation of quantum theory is to explain the physical significance of the |ψ>. In this paper we have shown that one of the best way to make of interpretation of wave function is to take the wave function as an operator.

Optical and Electrical Properties of Organic Conducting Polymers

2014 ◽  
Vol 8 (1) ◽  
pp. 1457-1463
Author(s):  
Salah Abdulla Hasoon
Keyword(s):  
Electrical Properties ◽  
Conjugated Polymer ◽  
Polymeric Materials ◽  
Quantum Mechanical ◽  
Optical And Electrical Properties ◽  
Electrically Conducting ◽  
Temperature Ranges ◽  
Lithium Tetrafluoroborate ◽  
Absorbance Peak ◽  
Polymerization Method

Novel electrically conducting polymeric materials are prepared in this work. Polythiophene (PT) and poly (3-Methelthiophene) (P3MT) films were prepared by electro-polymerization method using cyclic voltammetry in acetonitrile as a solvent and lithium tetrafluoroborate as the electrolyte on a gold electrode. Electrical properties of P3MT have been examined in different environments using UV-Vis absorption spectroscopy and quantum mechanical ab initio calculations, The observed absorption peaks at 314 and 415 nm, were attributed to the n-π* and π-π* transitions, respectively in the conjugated polymer chain, in contrast, the observed absorbance peak at 649 nm, is responsible for electric conduction. The temperature dependence of the conductivity can be fitted to the Arrhenius and the VTF equations in different temperature ranges.

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