Questions tagged [theoretical-chemistry]
For questions seeking answers deduced from or composed of theories regarding the chemical substances and about models and methods of theoretical chemistry.
619
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Why Car Parrinello Molecular Dynamics doesn't need an SCF calculation at every time-step?
Reading the various terms of the Lagrangian in CP-MD I'm trying to understand why there is not an SCF procedure hidden there.
In fact, it seems to me like the second term of the Eulero-Lagrange ...
- 101
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How does ML / AI models can help us in high throughput screening studies?
I am a chemist interested in applying fast methods to search for suitable molecular candidates for several applications (let's say HOMO LUMO gaps, excitation energies, etc.) As a consequence, I ...
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Second derivative terms of DFT functional
Given the density functional to KSF matrix elements
$E^{XC} = \int dr f(r,R)$,
where $r$ and $R$ denotes electronic and nuclear coordinates, respectively.
Suppose we have an LDA functional, which can ...
- 193
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Experiment on pH vs Rate of Electrolysis - what do the results actually say?
My experimental setup looks at using different pH solutions (of $\ce{H2SO4}$ and $\ce{NaOH}$) for electrolysis of water with a Hoffman setup and then measuring the rate of production of gas (note this ...
- 39
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How to Determine the State of Matter of a Molecule
While many videos and even answers exist on this site about finding whether a compound is soluble in water to determine if its state symbol should be "(aq)." However, across the internet I ...
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Minimum volume of benzene with percentage yield
The overall yield for the synthesis of N-phenylethanamide from benzene was found to be $35.2\%$.
Calculate the minimum volume of benzene, in $\mathrm{cm}^3$, required to make $10.0\, \mathrm{g}$ of N-...
- 127
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38
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Resonance stabilization : lowering of kinetic energy or electron repulsion?
Resonance stabilization, or delocalization stabilization, occurs when the overall energy of the molecule is lowered compared the localized "resonance structures".
In solid state physics, or ...
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57
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Behavior of polyanionic silicate chains in silico
I am trying to understand the stability of charged linear molecules, more specifically these, which contain periodically repeated high electron affinity parts, such as single-bonded oxygen (radicals). ...
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How to find the global minima of a supramolecular complex in computational chemistry?
So this is more of a complex problem, and my masters thesis could greatly benefit if I find an answer to this.
Essentially, I have a supramolecular inclusion complex. There is this molecule A (the ...
- 11
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How does graphite content affect the conductivity of pencil lead?
My peers and I started an experiment to test whether we could use the conductivity of a piece of pencil lead to determine its grade (that is, whether it is 2H, HB, 3B etc.). The paper Observational ...
- 593
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Define a rate-determining step and an energy barrier for a multi-step reaction profile
I am currently making reaction profile by means of DFT calculations. I am able to correctly draw a whole reaction profile.
However, I am struggling to find what exactly is the energy barrier of a ...
- 398
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Question about conservation of amount of substance
if I consider the reaction : $$A \longrightarrow B+C$$
by what we call conservation of the amount of substance, we have $$nA_{0}=nA+nB=nA+nC$$
But for me the conservation says that $$nA_{0}=nA+nB+nC$$,...
- 9
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51
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How to calculate theoretical value of mass output using electrolysis with different electrolyte concentrations?
I am writing a research paper on a zinc-copper electrolysis experiment observing the mass output of Zinc on a copper cathode, in which I am changing the concentration of the zincsulfate electrolytic ...
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Energy Decomposition Analysis for SN2 involving ambident nucleophiles and an alkali metal counterion
I am wanting to perform an EDA on transition state structure of the nucleophilic attack of an ambident nucleophile (2 atoms that could be used in nucleophilic attack on the same molecule) on a benzyl ...
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Force contribution of image atom using periodic boundary conditions
This is maybe a stupid question but lead to a discussion between me an my colleagues. If we use periodic boundary conditions and an atom has itself as neighbor do we need special care of this ...
- 556