Unanswered Questions

7,829 questions with no upvoted or accepted answers
38 votes
1 answer
1k views

How does the silver nucleate on glass in Tollen's reagent mirroring?

I want to know the exact mechanism for how silver would start to grow during a mirroring with Tollen's reagent. I've made two pictures to illustrate how I see the nucleation/growth process of silver ...
23 votes
0 answers
2k views

How to calculate transition dipole moment from two known wavefunctions

I am interested in calculating the transition dipole moment (TDM) from the information from two wavefunctions of different states. This is somewhat similar to calculating the molecular dipole moment ...
21 votes
0 answers
8k views

In rovibrational spectra, when exactly is the Q branch forbidden?

I'm aware that the Q branch ($\Delta j = 0$) is usually not observed in rotational-vibrational spectra of diatomic molecules in the gas state, however, I've heard different things about when exactly ...
20 votes
1 answer
405 views

Some materials emit more photoelectrons than others - why?

I've been experimenting with some materials by changing the wavelength of the incident light on the material and detecting photoelectrons, like in the diagram below: I might get a response that looks ...
19 votes
0 answers
2k views

Do Cyclohexane-1,3-diones Give Positive Haloform Reactions?

Recently a post appeared on ChemSE asking why cyclohexane-1,3-dione (dihydroresorcinol) 1a doesn’t give a positive iodoform test. Unfortunately, the post was subsequently taken down after several ...
19 votes
0 answers
364 views

Manuals for a Cahn TG-171 Thermogravimetric Analyzer

Recently a Cahn TG-171 Thermogravimetric Analyzer was donated to my school. We did not get a service or user's manual with it, and some of it still needs to be put back together. I have tried to ...
18 votes
0 answers
427 views

Does CN4 with the following structure exist?

I am a mathematician, not a chemist, so my questions are rather combinatorial. I am intrigued by the possibility of the following binary compound: $$\ce{\overset{-}{N}=\overset{+}{N}=C=\overset{+}{N}=\...
17 votes
1 answer
347 views

Correlation between 1H and 13C shifts - coincidence or not?

A quick glance at any table of typical chemical shifts will reveal that the chemical shifts of protons $(\delta_\mathrm H)$ tend to correlate pretty well with the chemical shifts of the carbons to ...
15 votes
0 answers
267 views

Tetrahedrane Properties and Analogs

I took a look into some tetrahedrane ($\ce{C4H4}$) analogs, platonic hydrocarbon, basically very strained tetrahedral geometry at every carbon. I was wondering what will be the predicted delta H of ...
15 votes
0 answers
1k views

Can we use phosphorous triiodide in Hell-Volhard-Zelinsky reaction?

With the help of HVZ reaction, we can get alpha-chloro or alpha-bromo carboxylic acid. But can we make alpha-iodocarboxylic acid with the help of HVZ reaction? I could not find any reference of HVZ ...
13 votes
0 answers
286 views

MNDO integrals in the global coordinate system

In MNDO and its descendants (Sewart's PMx models, Austin's AM1, MNDO/d, etc.), the nonvanishing two-center two-electron "coulomb integrals" are evaluated via a classical multipole expansion in a local ...
13 votes
0 answers
498 views

What is d-orbital collapse?

When I was perusing the works of Schwarz on atomic structure, I came across the unfamiliar term of d-orbital collapse. He describes it as a variation in energetic sequence from group 1 to 3 elements ...
13 votes
0 answers
198 views

Can pi backdonation occur on non-metal centers?

The common example of back-donation is the interaction of a CO molecule with a metal center (d-orbitals) on a surface. Can a similar mechanism occur between CO and a non-metal center, like oxygen on ...
13 votes
0 answers
352 views

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 ...
13 votes
0 answers
316 views

Rotation around CC bond in 1,2-dioxetane: transition states and local minimum structures

TLDR: What: Potential energy surface associated with rotation around CC bond in the ring-opened version of 1,2-dioxetane. How: State average(4)-CASSCF(12,10)/VTZP constrained geometry optimizations ...

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