Unanswered Questions
7,281 questions with no upvoted or accepted answers
33
votes
2answers
967 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 ...
22
votes
0answers
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 ...
19
votes
0answers
335 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
0answers
1k 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 ...
18
votes
0answers
291 views
Some materials emit more photoelectrons than others - why?
Again, I'm a physicist turning to chemists (so bear with me). So I've been measuring some materials by changing the wavelength of the incident light on the material and I have a detecting tip like in ...
17
votes
1answer
6k 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 ...
16
votes
0answers
197 views
Tetrahedrane Properties and Analogs
I took a look into some tetrahedrane (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
0answers
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 ...
14
votes
0answers
182 views
What happens when para-water ice is suddenly melted?
Background (hydrogen)
In the case of recently liquified hydrogen (which is quite cold of course) it must be re-equilibrated before loading on to a rocket as fuel to avoid a sudden exothermic ...
14
votes
1answer
286 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}=\...
13
votes
0answers
221 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
0answers
343 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
0answers
177 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
0answers
306 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
0answers
311 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 ...
