Unanswered Questions

6,052 questions with no upvoted or accepted answers
43
votes
0answers
960 views

How can I update a map/mesh and coordinates in a PyMol session file?

I have a PyMol session file I was using to create my figures. It contains a protein and ligand broken into several groups of atoms with a fair bit of overlap. There are also a few meshes built from ...
22
votes
0answers
379 views

Single-molecule magnet with electrically-controlled permeability: How does the Titan Shield from Deus Ex work?

In a recent installment of Deus Ex game series there is an augmentation called "Titan Shield" (it has nothing to do with $\ce{Ti}$ element): A neodymium skin underlay matrix built of nano-...
22
votes
3answers
709 views

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

I'm trying to figure out how exactly does the silver 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 on ...
19
votes
1answer
11k views

Melting and boiling point trend in Group II

The following picture shows the melting and boiling point trends down group II elements. I have added question marks where the variability in data was rather disturbing (over two hundred degrees ...
18
votes
0answers
702 views

Ambimodal transition states in some organic reaction pathways

In many computational studies, mechanisms appear to have so-called ambimodal transition states, i.e. a transition state which can lead to multiple products, in conflict to the common undergraduate ...
16
votes
0answers
146 views

Synthesis Golf XI: Hyperielliptone HA

It has been a little over a year since the last synthesis-golf was posted. I have talked to orthocresol and would like to help revive the tag! A full FAQ post has been written on chemistry.meta.SE, ...
16
votes
0answers
302 views

f-electrons in chemistry of heavy transition metals

In one lecture on recent MCR-X conference I was puzzled by a side-note "f-hole is critical to describe DoS of $\ce{IrO2}$ correctly." The context was DFT periodic plane-wave calculations with ...
14
votes
0answers
167 views

Mechanistic Explanation of Circular Dichroism

I'm wondering if someone can give me a physically motivated reason for why chiral molecules interact with left and right circularly polarized light (LCP) (RCP) differently. Particularly, a quantum ...
14
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 ...
14
votes
1answer
2k views

Why is the endo product the major product in a Diels-Alder reaction?

I understand that the endo product is, at least in all cases in my textbook, the major product in a Diels-Alder reaction. However, I don't understand why this is the case. The explanation in my ...
13
votes
1answer
4k 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 ...
13
votes
1answer
389 views

How to treat pressure in computational chemistry?

I have a reaction where a gas at high pressure and a solution with all kinds of species is involved. How do I take pressure correctly into account to get reasonable values for $G$? Do I calculate ...
12
votes
1answer
470 views

Why are palladium and platinum carbonyls unstable at room temperature?

By palladium and platinum carbonyls, I mean the mononuclear, homoleptic, charge-neutral, binary carbonyl complexes of the form $\ce{M(CO)_n}$ and not any heteroleptic complexes like $\ce{Pd(CO)(PPh3)3}...
12
votes
0answers
142 views

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}...
12
votes
0answers
143 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 ...

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