6
votes
Accepted
Non-Arrhenius temperature dependence of bimolecular reaction rates at very high temperatures
The cases you describe are
(a) In reactions with a low activation barrier with respect to thermal energy ($k_BT$) the rate constant will be limited by diffusion together of the two species since they ...
- 30k
6
votes
Accepted
Is there an algebraic form for the textbook reaction coordinate curves?
Here is a function that works: https://www.desmos.com/calculator/cqwgfj2nzt
The general function would be
$$ a \left( \frac{b}{1 - e^{5-x}} - \frac{c}{1 - e^{10-x}} \right)$$
I'm sure you could ...
- 39k
5
votes
Is there a difference between Hartree-Fock method and LCAO?
Obviously, this is a topic which much can be written on. I'll try to keep it short and simple. The LCAO concept merely says that MOs are formed from AOs through linear combination, i.e.
$$\psi_n = \...
- 71.1k
5
votes
Is tetraoxidocobaltate(V) low-spin
The answer, at least for potassium tetraoxidocolbate(V) in dilute tripotassium phosphate solid solution, appears to be high-spin despite the high oxidation state of the cobalt.
Brendel and Klemm[1] ...
- 53.1k
3
votes
What happened to the Klopman - Salem equation?
Although its importance from a "conceptual" point of view (it justifies both the frontier orbitals theory and the hard and soft acids and bases theory) this equation is very rarely used in ...
- 31
3
votes
Accepted
Are there any examples of tricoordinate hydrogen?
Magnesium hydride, with the rutile structure, has each hydrogen atom bonded to three magnesium atoms, but this is generally considered predominantly ionic (see here for a discussion of the structure ...
- 53.1k
2
votes
Is there an algebraic form for the textbook reaction coordinate curves?
You can simply use matplotlib to plot a smooth line connecting points
...
2
votes
Can cyclopropane be synthesized from propan-1-ol?
At first look at how cyclopropane can be produced from a haloalkane
This is the creation of cyclopropane by Zn metal reduction of terminal vicinal dihalide. Actually cyclopropane is a highly strained ...
- 728
2
votes
Accepted
Why is the local coupling constant (vibronic coupling) given in eV?
The local coupling constant is typically given in units of energy, such as electronvolts (eV), because it represents the strength of the coupling between the electronic and vibrational degrees of ...
- 490
1
vote
Accepted
Doubt on vibronic transitions
There are two effects, vibronic transitions and vibronic coupling.
In the BO approximation the wavefunction is a product of electronic $\psi$ and vibrational $\chi$ wavefunctions, for the ground state ...
- 30k
1
vote
Why does Euler's Number appear in so many equations?
Euler's number $e$ as such is less prominent than the exponential function $f(x)=\exp(x)$. It is this function, not $e$, that appears widely. For instance, the exponential function appears ...
- 53.1k
1
vote
Accepted
Highest possible temperature
One can look for highest temperature of the universe in a singularity of a black hole where the energy density is infinite according to General Relativity but super high and finite according to the ...
- 307
1
vote
How do you know if a bond according to VB theory consists of 2 "3 electron bonds" or one "fully paired" bond?
You can't, really.
Trihalide ions, $\ce{X3^-}$, are known for all halogens with stable isotopes ($\ce{F,Cl,Br,I}$). Conventionally they are regarded as having a two-elecron bond delocalized between ...
- 53.1k
1
vote
Accepted
Difficult in grasping "the extent/limit of conformational space of a compound until it change its stereochemistry"
You have the right idea that conformational space can be partitioned by configurational isomers. The clearest cases are where you have to break bonds to end up with another configurational isomer, but ...
- 275
1
vote
Group theoretical condition for an integral to be zero
I was not completely happy with any answer so far, so here is my take on this:
We consider some integral
$$
\int_{\Omega} f d\Omega
$$
over some volume $\Omega$, ideally over $\mathbb{R}^d$, where $d$ ...
- 11
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