Unanswered Questions
496 questions with no upvoted or accepted answers
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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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Gaussian Program Error for Linear Triatomic Molecule
I am trying to calculate the Hessian and vibrational frequencies of OCS (and eventually some anharmonic properties) with Gaussian09. However, the program always fails and I end up with the following ...
- 111
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Why is silicon dioxide a network solid while sulfur dioxide is a molecular gas
In my understanding sulfur dioxide’s Lewis structure has one lone pair on the centre atom (sulfur) with one pi bond to each oxygen atom, while silicon cannot form these silicon-oxygen pi bonds. Both ...
- 53
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Individual Oxidation Number of Nitrogen atoms in HN3
I'm confused about the individual oxidation number of nitrogen atoms in hydrazoic acid.
My teacher told me that oxidation state between similar atoms result in zero oxidation number on both the atoms ...
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Is the $2p$ RPD defined along the z-axis?
In MIT $5.111$ class (lecture $6$), we are to compare the most probable radius of a $2s$ orbital and a $2p$ orbital. The graph used by the professor represents the RPD versus $r$:
My question is: in ...
- 257
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Doubly occupied orbitals in quantum chemistry? (openfermion.org)
I am interested in diagonalising the fermionic Hamiltonian of small molecules, such as LiH in second quantisation.
The Hamiltonian is
\begin{align}
H(R) = \sum_{ij} h_{ij}(R) a_i^\dagger a_j + \frac{1}...
- 111
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Finding the relative position of the molecule in the adsorbate and adsorbent by minimizing the Hamiltonian
I am trying to model an adsorbing process (or more precisely, Heterogeneous catalysis process between solid catalyst and gas reactants). One of the step is to minimize the Hamiltonian by optimizing ...
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Do Electron-Withdrawing-Groups give an hypsochromic shift or a bathochromic one? and why?
I'm not familiar with this topic,but i know that bathochromic shifts occur when the energy gap between energy levels of the substituted molecule, are lower than the unsubstituted one;viceversa ...
CommunityBot
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Absurd result for the selection rules in the three-dimensional PIB
By using time-dependent perturbation theory and some simplifying assumptions, we know that a transition for a charged particle $q$ from a quantum-mechanical state $m$ to $n$ is allowed if and only if
\...
- 3,684
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geometry of [Co(CN)₄]4-
This is a question that arises from the jee advanced 2024(india) exam.
I am not sure whether the above complex exists.However it has been asked in the paper.
in the exam we are supposed to use only ...
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In the RDF plot of a particular orbital, why don't peaks come with radius greater than that of the max peak?
While studying radial distribution function (RDF) plots I see that orbitals (3s, 2s, ... 3p etc) often have peaks at radii less than that of the maximum peak. Assuming the probability of finding an e-...
- 22.5k
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Why is the translational motion left out of the energy eigenvalue in the hydrogen atom?
When solving the hydrogen atom, since we have two particles, the wave function has the form $\psi(\mathbf{q}_1,\mathbf{q}_2)$. Generally, textbooks proceed to demonstrate that an interacting two-...
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Helium ground state with Hartree–Fock using angular dependent functions
To compute the helium ground state (singlet) in Hartree–Fock theory we have to solve this equation:
$$ \left[ - \frac{\Delta}{2} - \frac{Z}{r} + \frac{1}{2} \int d^3 r' \frac{\vert \Psi(\boldsymbol{r'}...
- 38.4k
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Restriction of back bonding in tris(dimethylamino)borane
J.D. Lee Concise Inorganic Chemistry [3, p. 78] mentions that
The bond length order of the B-N bond in the following compounds is
$\ce{B(NR2)3}$ > $\ce{HB(NR2)2}$ > $\ce{H2B(NR2)}$
and the ...
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Confusion in comparing contribution of resonance structures in Hydrazoic acid
Given below is the resonance hybrid of $\ce{HN3}$(Hydrazoic acid)
And these are the resonance structures below:
If the second resonance structure had contributed more, then the two bond lengths ...
CommunityBot
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