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Solving the Schrödinger equation for a rotating triatomic linear molecule

This source is showing that solving the Schrödinger equation for a triatmoic linear molecule yields the same formula for the rotationaI quantum states $BJ(J+1)$ as for dipoles. For dipoles, the total ...
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408 views

Mulliken Spin Density

I would like to know if a Mulliken population analysis to calculate spin densities is in general a valid choice. I see that it is made use of, for example here1. So up to-date researches apparently ...
6
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78 views

Are platinum metal whiskers very unusual?

Over 20 years ago I pulled my first set of platinum spark plugs out of a car because the engine was missing badly. Two of the six plugs each had one whisker in the gap between electrodes. One crossed ...
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89 views

Why does BCF (boron carbofluoride) not exist?

$\ce{BCF}$ (boron carbofluoride, or carbon borofluoride, not to be confused with another so-called BCF molecule that has nothing to do with it) should exist as a vapor molecule with the bonds $\ce{B≡C-...
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49 views

Are there acid/base processes in aqueous solution that are so slow that they are kinetically controlled?

This question came up in figuring out what the fundamental differences are between redox chemistry and acid/base chemistry (if any). In redox chemistry, strong oxidants and strong reductants can co-...
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203 views

Hartee-Fock vs tight binding and others

I was reviewing many electron computational methods recently and got a bit confused about relation between different approaches. In particular in what is essential elemental difference between Hartree-...
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3k views

How is NaBH4 able to reduce tertiary alkyl halides to alkane but LiAlH4 create an alkene?

When attacking tertiary alkyl halides, aren't both of them just supposed to follow $\mathrm{S_N2}$ and substitute the leaving group with Hydride ion? Apparently only $\ce{NaBH4}$ does it and $\ce{...
6
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54 views

Using Le Chatelier's Principle to Change Mechanical Energy to Chemical Energy

I was interested in an application of Le Chatelier's principle, where an increase in pressure could result in a decrease in the moles of gas. In particular, a situation where when the pressure ...
6
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197 views

How to extract force constants for normal modes from ORCA?

I am following the computational method described in Scientific Reports.[1] Where the authors analyze the contribution of each excited state normal-modes to the shift of the transition energy. For ...
6
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332 views

OpenBabel: how to get correct SMILES from Gaussian output?

I would like to get the molecular structure as SMILES from Gaussian output files. OpenBabel seems to be the tool made for such tasks. However, the structure is not always correct. One example: ...
6
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150 views

Where to find experimental spin-orbit coupling constants?

I am searching for experimental spin-orbit coupling constants, particularly for main group elements and Cr(0) to calculate correlation consistent Composite Approach (ccCA) energetics. This method ...
6
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60 views

Cyclic polyynes

Cyclic polyynes have been proposed as theoretical compounds to illustrate the “particle on a ring” model discussed in many quantum chemistry courses. I've looked it up on Wikipedia but there it's not ...
6
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104 views

Can you use a photon's torque to change a molecule?

Can you use the torque of a photon to change bond angles, etc.? 11-Cis-Retinal to the all trans version, in the eye, is a good illustration [1]. Note: This phenomenon can be observed by closing ...
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172 views

Is any symmetry element conserved during a supra-antarafacial cyclo addition of two cis-butadiene units

I tried to construct a correlation diagram for the [4+4] cyclo addition of two cis-butadiene units. But I failed to construct any meaning full orbitals for the "educt" side where the two butadiene ...
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79 views

Do "random" "2D" polymers constrained to a box actually form "space filling" curves?

Background: The self avoiding walk model is (allegedly) a reasonable model for polymers, at least with respect to certain "universal" (i.e. lattice independent) constants -- see section 1.1. in this ...
6
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1answer
1k views

Which one is the stronger Lewis base: diethyl ether or tetrahydrofuran?

I am trying to understand Lewis bases (bear with me, I am a physicist). I was asking myself how diethyl ether and tetrahydrofuran compare with respect to their properties as solvents in electrophilic ...
6
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98 views

Why the use of MD simulations is less popular for the study of carbohydrates?

In classical all-atom MD simulations, the force fields for proteins, nucleic acids and lipids seem to be more well developed than carbohydrates. It seems to me that the use of MD simulations is not so ...
6
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248 views

How to evaluate the expectation value of the Hamiltonian for a three electron Slater determinant?

I'm having trouble with a few concepts dealing with slater determinants and many electron systems. In particular, when dealing with 3 electron systems, I know that $$ \psi_0 = \frac{1}{\sqrt{6}} \det ...
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549 views

Calculation of rate constant for bimolecular reaction from Gaussian DFT calculations

I am working with a bimolecular reaction for which I have computed the energy profile. I have output files for TS and reactants which I intend to use for rate constant calculations. From TST we have: ...
6
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1answer
483 views

The carbon-13 chemical shift of acyl chlorides vs ketones

In lectures, we were taught that ketones and aldehydes tend to have chemical shifts of around 200 ppm, while acid derivatives (carboxylic acids esters etc) tend to have values around 160–170 ppm. The ...
6
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250 views

What compound has the strongest optical rotation of polarised light?

A question recently asked here whether compounds know to be chiral can have non-measurable optical rotations: Are there chiral compounds that don't rotate plane-polarized light?. Apparently they ...
6
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161 views

Vibrational Self-Consistent Field

There are a few things about VSCF that I don't understand: Which coordinates do you work in? If you work in normal mode coordinates, how do you evaluate the effect of the average of one normal mode ...
6
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0answers
826 views

How does the Jahn-Teller distortion result in both elongation and compression?

Recently, I have been reading up on the Jahn-Teller effect and I have read articles and posts on it, such as What is the mathematical basis behind the Jahn-Teller effect?. However, many of these ...
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269 views

What are metal zip tags and belt buckles made of?

Metal zipper tags and belt buckles melt very easily and can be melted by heating it in the stove for 5 minutes. But other metals like aluminium refuse to melt even after hours. If you leave it ...
6
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483 views

Why can't beryllium react with hydrogen gas directly to give hydride?

I read in a textbook that all alkali metal and alkaline earth metal can react with hydrogen directly to give hydride except for beryllium. I want to know the reason why because I know that $\ce{BeH2}$ ...
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2k views

SN1 reactivity order for chloromethyl methyl ether and trityl chloride

Compare the reactivity order towards SN1 reaction for: (2-chloropropan-2-yl)cyclopropane $\ce{CH3OCH2Cl}$ $\ce{Ph3CCl}$ Owing to the exceptional stability of cyclopropyl ethyl ...
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341 views

pKa of different sites of butanone

From what I can tell, deprotonation of the central hydrogen leads to the more thermodynamically stable product (most substituted double bond. i.e. most stabilization by hyperconjugation). Therefore, ...
6
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648 views

Reaction rate constants for methane combustion

I can't find a rate constant or activation energy for the methane combustion reaction given by: $$\ce{ CH4 + 2O2 -> CO2 + 2H2O}$$ Do all reactions have a rate constant? The NIST web site lists ...
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38 views

Fatty Acid synthesis - enzymes that vertebrates cannot make

In the fatty acid elongation and desaturation reactions, how are enzymes that insert double bonds after the 9th carbon different from those that insert at the 9th or before? Vertebrates (at least ...
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744 views

Molecular visualization software for Raspberry Pi?

I've been using our lab's code MCMD on my Raspberry Pi for fun and exploratory purposes. I'm trying to find a VMD, Avogadro, Ovito, or other equivalent that is usable on Raspberry Pi, e.g. to view ....
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471 views

Thermophysical properties of liquid Galden LS 230 between 25 °C and 230 °C

I'm looking for thermophysical properties of Galden LS 230, a liquid polymer (PFPE) produced by Solvay (https://www.solvay.com/en/markets-and-products/featured-products/Galden.html) at temperatures ...
6
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3k views

Which is the correct mechanism for the ozonolysis of an alkyne?

According to Organic Chemistry by Jonathan Clayden, Nick Greeves and Stuart Warren (2nd edition), the mechanism for alkene ozonolysis is given as In Advanced Organic Chemistry, Part B: Reactions and ...
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570 views

Why is nitrogen dioxide brown?

Nitrogen dioxide (NO2) is a reddish brown molecule, while its dimer nitrogen tetroxide (N2O4) is colorless. Can you give a reasonably detailed explanation for this from electronic structure theory? ...
6
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0answers
238 views

Conductivity measurements of demineralized water - Unexpected results. Looking for explanation

I'm trying to measure the conductivity change of demineralized water over a few days. But I get results I can't explain. Setup This is the circuit and cell I'm using: Where $R_x$ is the ...
6
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0answers
733 views

Coordination Numbers and Hybridization schemes of anions

Draw the molecular structures of (a) the borax anion, $\ce{[B4O5(OH)4]^2-}$ (b) the peroxoborate anion, $\ce{[B2(O2)2(OH)4]^2-}$ ...
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87 views

Program to compute multipoles of water at CCSD(T)-F12 accuracy

I want to compute traceless cartesian electrostatic multipole moment tensors up to fourth order (hexadecapole), at CCSD(T)-F12 accuracy using a large basis set. I'd like to be able to choose the ...
6
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0answers
2k views

Why is o-fluorophenol a stronger acid than p-fluorophenol?

The $\mathrm{p}K_\mathrm{a}$ value of o-fluorophenol is $8.7$, while that of the p-fluorophenol is $9.9$. It's obvious that the inductive effect is more dominant at ortho-position, which results in a ...
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251 views

Why is it easier to add bromine to styrene than cinnamic acid?

Why is it easy to add bromine to styrene and why is it so difficult to add bromine to cinnamic acid? It is obvious that the $\ce{COOH}$ group of cinnamic acid affects the reaction quite a lot, but I ...
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326 views

Why does the presence of EWG's on the aryldiazonium ring increase the yield of a Meerwein arylation?

In my textbook, Strategic Applications of Named Reactions in Organic Synthesis, the author says the following regarding properties of the Meerwein arylation: The general features of this reaction ...
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119 views

Using Ethylene Glycol as anti-freeze in a biodigester gas storage system

I am busy building a bio-digester to produce biogas for cooking/water heating in a cold climate. I am using the 3 IBC tank solution. Tank 1 is the digester itself. Tank 2 is the gas storage unit. ...
6
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307 views

Canonical vs localized orbitals - stationary towards changes?

So regarding Koopman's theorem I found the the explanation that you should not use it to find the ionization potential of localized orbitals because, much unlike canonical orbitals they will not be ...
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2k views

How to dissolve slime jelly?

Suppose I have a small kid that had two cans of slime jelly (a Jelly made of water, glycerin, thickeners, dispersant, flavorings and pigments). And that two cans were inside a backpack, and somehow ...
6
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269 views

How to define the initial guess for the electron density?

This is a technical question. If I have a one-dimensional box of length L, and an electron density existing in the box and integrating to N electrons. And if I want to determine the electron density ...
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834 views

"Alternative" derivation of the spin-only formula

The spin-only formula $$\mu_\mathrm{so} = \mu_\mathrm{B} \sqrt{n(n+2)} = \mu_\mathrm{B}\cdot 2\sqrt{S(S+1)}$$ is usually a good first approximation to calculate the magnetic moment of transition ...
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1k views

Finding theoretical mechanism of sodium thiosulphate and hydrochloric acid

In class we conducted an experiment where we timed reactions between sodium thiosulphate and hydrochloric acid. We kept the concentration of the $\ce{HCl}$ constant, while changing the concentrations ...
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0answers
95 views

Is it correct to use the symbols (l) and (g) in every reaction?

I know that this question might sound stupid to most of the people, but for a chemist noob like me is not very clear. So, here's the main question: Is it appropriate to use the symbols (l) for ...
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0answers
35 views

Removal of nickel plating on MgB2 without damaging the boride?

I need to remove a nickel plating of a MgB2 wire without causing damage to the MgB2. I felt that electrolysis is the best method but I do not know what electrolyte to use for this. I also need to coat ...
6
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0answers
7k views

Why does reduction of naphthalene with nickel/hydrogen lead to trans-decalin?

Is there any reason why $\ce{H2/Ni}$ leads to trans-decalin? I knew from high school that catalytic hydrogenations are always syn.
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170 views

Equivalent Wyckoff position in different groups

I am not a chemist, I am a physicist, so please bare with me if what I am asking is rather obvious. If I have two symmetry groups ($P4/mmm$ and $P\!-\!1$), is there a way to find their respective ...
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4k views

Is iron(III) carbonate stable in water?

I searched for this onsite already, and also found the following answer on Quora: In aqueous environment, iron(III) is bound by water molecules and exists as $\ce{[Fe(H2O)6]^3+}$. Due to strong ...

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