All Questions
Tagged with computational-chemistry inorganic-chemistry
28
questions
1
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2
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454
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What is the hydrated diameter of a lithium ion？
When salts dissolve in water, the anions, cations, and strongly polar water molecules undergo hydration reactions, resulting in the formation of hydrated ions with a specific number of coordinated ...
- 31
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0
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38
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Can someone help with GAMESS input files for heavy atom calculations (MoS2, WS2, etc.)?
I'm doing computational research on transition metal dichalcogenides for my chemistry class and I want to calculate a transition state optimization for the reaction $\ce{MoS2 +N^- -> MoSN + S^-}$. ...
- 11
0
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0
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47
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Reduction of direct product representation
When we do the reduction of the reducible representation generated from the total wavefunction expressed as product of MOs of appropriate symmetry, we can find the direct sum of more than one ...
- 101
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0
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54
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Group theory and exact Eigenfunctions of Hamiltonian
I think I've understand why the real Eigenfunctions of Hamiltonian belong to a given irreducible representation and I've read that also MOs have to transform as irreducible representation due to the ...
- 101
2
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0
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42
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Commutating operators of angular momenta
I've studied the formal procedure to pass from the uncoupled basis set of individual angular momenta to the coupled basis set of total angular momenta for polyelectronic atoms.
I start from an ...
- 101
6
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4
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2k
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Given a CIF (crystallographic interchange format) file (and thus cartesian atomic coordinates), how can you find the bonds between atoms?
Applications like Vesta show bonds when viewing a CIF file; how could one algorithmically find all bond pairs?
Here is an example CIF file:
...
- 171
2
votes
1
answer
84
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Association constant calculation in 3:1 complexes
I have a question about calculating the association constant related to 3:1 host-guest complexes. I am using the UV-vis titration method, I know the stoichiometry from the molar fraction method which ...
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-4
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2
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242
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Milliliters of NaBr when changing molarity [closed]
I was very confused by this problem. I was able to get the molarity, but I wasn’t certain how to go from there:
If $\pu{2.60 g}$ of $\ce{NaBr}$ is dissolved in enough water to make $\pu{160.0 mL}$ of ...
- 99
1
vote
1
answer
72
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Why does Chem3D minimize nitrogen dioxide (radical) so badly? [closed]
I build from text O-N+O (the SMILES of this is O=[N+][O-]), I delete the hydrogen atom added automatically on N, then I start MM2 Minimization. Both the bond length ...
3
votes
1
answer
227
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Why is the OO-H dissociation is unlikely for the Caro's Acid?
Let us consider the Caro's Acid: $\mathrm{H_2SO_5 \equiv SO_3H-OOH}$.
It is widely known that the hydrogen tied with the $\mathrm{-OO-}$ group is pretty much unlikely to dissociate:
$$ \text {...
- 131
9
votes
1
answer
193
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How are unstable transition states determined? [closed]
The Wikipedia article about the Grignard Reaction says that
The addition of the Grignard reagent to the carbonyl typically proceeds through a six-membered ring transition state.
This got me ...
- 1,264
10
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1
answer
304
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Have IH₃ and IH₅ already been synthesized?
I've seen a paper by Sikalov [1] that says that $\ce{IH3}$ and $\ce{IH5}$ should be observable. Has anyone actually tried to synthesize such molecules?
References
Sikalov, A. A. Hypervalent Halogen ...
- 101
1
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1
answer
117
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What is the correlation between electronegativity and the sharing of electrons?
For example in a C-O bond, the electronegativity difference is 1.2. does this mean that the Oxygen has 1.2 of the shared electrons and Carbon 0.8 (or some other numbers)? Is there a specific equation ...
- 21
-1
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1
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489
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How to give different Basis set to different atoms in molecules using GAMESS-US [closed]
I am new to GAMESS-US, I am trying to do UHF for DyC10H10 while giving different basis set to Dy, C, H to reduce the computational cast.
Until I tried with following input using manual.
OUTPUT
*** ...
- 11
1
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0
answers
446
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How to understand MO diagrams for cationic octahedral transition metal complexes
I am having problems understanding the construction of MO diagrams in octahedral transition metal complexes within ligand field theory (LFT) when the metal center is asumed as an cation:
I am ...
0
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1
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89
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Maximum metal-metal distance for antiferromagnetic coupling
Imagine a transition metal complex with multiple open-shell transition metal cations. If the metals are relatively close in distance, it is possible that antiferromagnetic coupling will occur between ...
- 1,352
-1
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1
answer
66
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Help understanding the equation for Spin Energy in Zero Field
I’m working with a system that experiences spin frustration and for me this is the first time dealing with such a phenomenon. To grasp the concept, I’ve decided to go to the basics and read the ...
- 485
7
votes
1
answer
283
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D6h symmetry clusters- orbital classification confusion!
I was am simulating high symmetry clusters D6h in several programs such as molcas and gaussian. I understand that the highest symmetry used in these programs is D2h and therefore there would be mixing ...
- 167
1
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1
answer
173
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How to reconcile conflict between assumed oxidation state and the most stable multiplicity from electronic structure calculations?
Consider either of the small, neutral molecules containing two Zn atoms below. If I were to determine the oxidation state of Zn from this molecule, I would formally assume each Zn to be Zn(I) in order ...
- 1,352
4
votes
0
answers
140
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Briggs-Rauscher numerical model
I want to use the Briggs-Rauscher experiment to demonstrate oscillating reactions, and then explain it using a numerical model. How much is known about this reaction? Is it possible to write down a ...
- 141
6
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0
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207
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I found transition states (TS), but calculations aren't supported by experiment. Do I look for more TSs or somewhere else?
I'm using Gaussian to investigate a catalyst system.
Experimental evidence showed that one of three analogues (R = phenyl, Ph), yielded a benzosultam
when treated with 2,4,6-...
- 61
1
vote
1
answer
535
views
What will be the coordination number in Fe(0)?
Fe(0) has its electronic configuration $\ce{3d^6 4s^2}$ in the ground state. In this case multiplicity will be either 1 or 3 during excitation. If multiplicity is 1, the vacant excited orbitals are $\...
19
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2
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2k
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Do bare protons exist, even transiently, in aqueous solution?
Generally $\ce{H^+}$ ions in water remain in the form of hydronium ions ($\ce{H3O+}$), and not as "free" aqueous protons, as far as I've been taught.
My question: is this always the case, even when ...
- 429
14
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2
answers
741
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Molecular mechanics force fields for metals?
I know of several general molecular mechanics methods suitable for metals, including Dreiding and UFF.
I know it's difficult to get many things right for such classical treatment of inorganic / ...
- 27.9k
12
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1
answer
2k
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Can PBE (and LDA) actually be a better choice sometimes?
Part of my work as an inorganic chemist is to investigate the magnetic coupling between metallic centers in coordination compounds. After some time, I've noticed that the classic PBE functional is the ...
- 485
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0
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47
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Internal treatments of gas cylinders for toxic gas mixture
The values of toxic components like $\ce{H2S}$, $\ce{NO}$, $\ce{SO2}$, etc. [in ppm level] get decreased after a while due to adsorption phenomenon. Manufacturers design some internal treatments in ...
- 11
2
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114
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Making a reasonable slab of alpha quartz
I want to perform a molecular dynamics simulation with alpha-quartz as my mineral surface. I want to study adsorption of water on alpha-quartz. The most dominant error that I came up with is the ...
- 141
5
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1
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144
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Are there computer searches for new theoretical minerals in a similar vein to Folding@Home or SETI@Home?
As a surprise gift to a friend I would like to discover a new theoretical mineral and have it named after them. I have some understanding that not all minerals have been discovered, and some minerals ...
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