Unanswered Questions
1,412 questions with no upvoted or accepted answers
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What is the largest coupled cluster calculation that has ever been done (as of March 2019)?
I am doing some research and trying to make sure the numbers I am reporting are accurate.
I found that the paper by Sylvetsky et. al. says:[1]
We were, however, able to complete a ...
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Calculating Triplet-Triplet Spin-Orbit Coupling
According to the Q-Chem manual [1], the singlet-triplet spin-orbit couplings between a singlet excited state $I$ and a triplet excited state state $J$ is:
$$\langle\Phi_\text{singlet}^I|\hat{\mathrm H}...
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Doubt in Zeeman effect for sodium spectrum
I am reading an atomic molecular physics book (for Indian universities). You may not familiar with it. But you can download it from the link if you wish.
So in the book it is mentioned that for normal ...
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Why are IUPAC's definitions of exo- and endothermic disconnected from the direction of heat flow?
I'm wondering if anyone can provide a rationale for IUPAC's definitions of exothermic and endothermic since they disconnect these terms from the direction of heat flow.
Specifically, here are IUPAC's ...
CommunityBot
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In a molecular dynamics context, is the methyl rotation in propene a symmetric or asymmetric internal rotor?
In a prior question, I asked about the (a)symmetry of the potential energy surface of the methyl rotation of propene. In that context, the kinetic energy of the nuclear motions is of course assumed ...
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Quenching rates in nucleation MD simulations
I am trying to perform nucleation simulations with molecular dynamics. To prepare the metastable fluid, I am equilibrating at temperatures about 30 K above the melting temperature, and then "quenching"...
- 71.6k
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multielectron spin-orbit coupling and energy level
For multi-electron atoms for which the Hamiltonian (including the spin-orbit coupling) reads
$$H=\sum_i T_i-Z\sum_i V_i+\sum_i V_i^{\text{s.o.}}+\sum_{i>j}V_{ij}$$
The $T_i$ are the kinetic ...
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Will the sulfur-iodine cycle and Haber Method work at lower pressures and temperatures?
I have a year-long research project next year in my senior year of high school, in which we have to make some product or prototype to solve some issue.
My interest was in the Liquid Fluoride ...
CommunityBot
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What are the limitations of the Born-Lande' equation?
The Born-Lande' equation is used to theoretically calculate the lattice energy, $\Delta U$, of ionic compounds. It is often cited as such in literature,
$$\Delta U = -\frac{k_Az_1z_2Me^2}{4 \pi \...
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Why do chlorinated silanes have lower boiling points than their methane analogs?
The boiling points of the chlorinated silanes and methanes are given below:
$$\begin{array}{ccc}
\hline
\text{Species} & \text{Boiling point (X = Si) / }\mathrm{^\circ C} & \text{Boiling ...
- 71.6k
7
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Mathematical models of oscillatory chemical reactions
I am a mathematician working on real-life models in ordinary differential equations. I want to know if there are any models of oscillatory chemical reactions that consist of three ordinary ...
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Why does entropy increase in reactions that make more molecules?
I used to understand this (more molecules ⇒ more degrees of freedom), but do no longer, because the total number of atoms is conserved, so translational d.o.f. should just be turned into internal d.o....
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Is it possible to calculate electronegativity of surface atoms?
As the title asks, is it possible to calculate the electronegativity (EN) of specific atoms on extended surfaces (slabs), more specifically using computational methods? There are a few issues here I ...
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Beer's law: UV-Vis absorbance values exceeding 2
In classical analytical chemistry, absorbance values in Beer's law can theoretically range from 0 to infinity.
As general rule of thumb neither high, nor very low absorbance are used for ...
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Why is the R-branch in rovibrational spectroscopy bigger than the P branch?
I was conducting a rovibrational IR experiment and noticed that for HCl, the P branch is always lower in intensity than the R branch.
I already understand that the intensity of the spectral lines is ...
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