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Stack Exchange
Stack Exchange
4:23 AM
0
Q: Is there a theory behind selecting elements that may be successful in potential superconductors?

jonscaLooking at something like $\cf{ YBa{_2}Cu{_3}O{_7}}$ which was one of the first cuprate superconductors to be discovered, I'm always curious how the selection of these substances as likely superconductors comes about? Does it have to do with optimal crystalline structure, unpaired electrons, o...

superconductors
 
 
5 hours later…
Stack Exchange
Stack Exchange
9:12 AM
0
Q: Z-matrix of a series of 5 colinear atoms

F'xHow can I write a Z-matrix for the following complex? O==C==O H--O \ H I have managed to write: O C 1 a O 2 a 1 180 H 3 d 2 180 1 ? O 4 b 3 180 2 ? H 5 b 4 t 3 ? but I don't know how to specify the di...

theoretical-chemistry
0
Q: Where do I find Datasheets of Zeoliths?

martI'm looking into uses of zeoliths as water absorbers for heat storage and absorbtion cooling. However, I don't find hard numbers on the likes of absorption enthalpies at different tempteratures, saturation moistures etc. I'm not an institution, chemical suppliers are traditionally reluctant to s...

inorganic-chemistry thermodynamics
 
F'x
F'x
9:35 AM
@manishearth are you around?
 
Manishearth
Manishearth
@f yep
 
F'x
F'x
@Manishearth regarding your Pauli exclusion question, I wondered (but wouldn't ask on the site itself):
what's your proficiency with molecular orbitals and quantum chem?
 
Manishearth
Manishearth
Not much.
High-school level I could say, plus some extra reading
 
F'x
F'x
frankly, the problem with your questions are they can (as many) be answered at some many different levels
 
Manishearth
Manishearth
Aah
 
F'x
F'x
9:39 AM
what I mean is: when you're talking to someone with a formal education in these things, you can tell because they use the same terminology, fall back to the same concepts…
it's fine that you're asking questions like that, but they're harder to answer just because I don't really know in what model you want the answer
 
Manishearth
Manishearth
Aah..
1sec, brb.
 
F'x
F'x
no problem
 
Stack Exchange
Stack Exchange
0
Q: What dictates the lifetime of a solvated electron in a given solvent?

F'xSolvated electrons have a long lifetime in ammonia solutions, but their counterparts in water (called hydrated electrons) have a much smaller lifetime, of the order of microseconds in very pure water. (image from: Boero et al, Phys Rev Lett 2003, 90, 226403) What properties of the solvent acco...

solvents stability
0
Q: Pauli exclusion principle and resonance

ManishearthI've always been a bit uncomfortable with the concept of more than two electrons in a single orbital-like region(probability-wise) which occurs in resonance. This seems to disobey Pauli's exclusion principle. Let's take benzene for example. It has a delocalized cloud of electrons. These all ha...

quantum-mechanics resonance
 
F'x
F'x
well, I can't stay very long anyway, gotta go out with the kids
 
Manishearth
Manishearth
Alright, I'm back
 
F'x
F'x
9:44 AM
I'm withholding my answer on your question, because I realized I'm answering too many questions and should let others step in more…
 
Manishearth
Manishearth
Hmm, yeah, since I sometimes know extra stuff, I guess that grokking my level in a topic is hard
I'll clarify that (and next time as well)
 
F'x
F'x
I advise you to read up on molecular orbital theory, I think you'll really enjoy it
it's much simpler than the physics way of doing quantum mechanics, but it's very rich
 
Manishearth
Manishearth
@Fx I sorta know what it is, I mean I know how to find the MO config for most stuff and what an MO/ABMO is
But not too much in detail
 
F'x
F'x
symmetry plays a big role there, and you can actually find nice results and understand some molecular properties with that kind of tools
 
Manishearth
Manishearth
Yeah
 
F'x
F'x
9:48 AM
plus, you will have many more questions to ask while learning! :)
 
Manishearth
Manishearth
@Fx Yep :)
I seem to be asking a tad too many, but nobody else seems to be doing it so might as well ;-)
 
F'x
F'x
@Manishearth I have tried to ask some more expert-level questions, including some to which I might already know the answer but would welcome another explanation, to see if I'm right and if there is another way of explaining it
 
Manishearth
Manishearth
@Fx Yeah, I've done that on Phy.SE a bit
Not to seed the site, but just 'cos I want some better answers
 
F'x
F'x
I just hope we were going into public beta, because I think we can handle it now
 
Manishearth
Manishearth
@Fx Who decides? The system or the SE folks?
 
F'x
F'x
9:51 AM
someone from SE's team should be writing a Meta post soon to explain
ok, going, going, gone!
see you later
 
Manishearth
Manishearth
Cya
 
 
2 hours later…
Manishearth
Manishearth
11:59 AM
Ooh this is cool:
 
Richard Terrett
Richard Terrett
12:10 PM
@Manishearth - Sandwich compounds are a great way of breaking peoples' faith in intuitive concepts of bonding
pi-backbonding is another fun phenomenon
Question to anyone: how do I fulfill my beta commitment?
 
Manishearth
Manishearth
12:28 PM
@RichardTerrett > Once you've fulfilled your commitment on a new site by asking and answering a few questions, you'll be able to commit to another site. If you are very active, you may be able to re-use your commitment as soon as the second day of public beta. If you aren't active on the site, you won't be able to re-use the commitment until the end of the public beta, or until six months after the beta began.
PUBLIC beta
@RichardTerrett Yep :)
@RichardTerrett Actually I'm fine with the rest.. I'm not sure why the benzene has to bend, though. Broke my faith in benzene :)
but it's still pretty cool
 
Richard Terrett
Richard Terrett
The reverse happens for cyclooctatetraenide complexes
@Manishearth - Uranocene, the nuclear sandwich: en.wikipedia.org/wiki/Uranocene
 
Manishearth
Manishearth
@RichardTerrett I went ahead and asked why benzene gets bent, feel free to answer chemistry.stackexchange.com/questions/300/… :)
@RichardTerrett Ooh, nice
I like all these strange componds (eg urotropine, cubane, whatnot)
 
Richard Terrett
Richard Terrett
hang on
 
Manishearth
Manishearth
@RichardTerrett I now have a picture of a sandwich that explodes in my mind
thank you for ruining my appetite for sandwiches
:P
 
Aesin
Aesin
Actinides are complicated, and very rarely explode if you can help it. :/
 
Richard Terrett
Richard Terrett
12:41 PM
@Manishearth - Enjoy: en.wikipedia.org/wiki/Arsenicin_A
 
Manishearth
Manishearth
@Aesin "Nuclear sandwiches" do
 
Aesin
Aesin
(I do computational actinide chemistry.)
 
Richard Terrett
Richard Terrett
ooh cool
 
Aesin
Aesin
@Manishearth: Are you sure those aren't sandwiches made for the packed lunches of the nuclear family? :P
 
Manishearth
Manishearth
@RichardTerrett Now that's just downright strange
@Aesin Good one ;-)
 
Richard Terrett
Richard Terrett
12:43 PM
@Aesin - do you know G. Cavigliasso, by chance?
 
Manishearth
Manishearth
Gtg now, cya guys
BOOM
 
Richard Terrett
Richard Terrett
bye
 
Aesin
Aesin
Nope, I'm UK-based rather than Aus.
 
Richard Terrett
Richard Terrett
Ah, iirc he did some actinide stuff back in the day, either in france or the UK
 
Aesin
Aesin
Ah, well, I'm still a PhD student, so still rather new at this in the grand scheme of things. (Writing up, though.)
 
Richard Terrett
Richard Terrett
12:46 PM
me to
That reminds me, i think Schrock made an N2 activator with uranium as the metal, kinda cool
my bad, it was Cummins
 
Aesin
Aesin
For when you need a reaction that only a handful of academic facilities in the world can perform safely. :)
 
Richard Terrett
Richard Terrett
well, it beats making bullets out of it
 
Aesin
Aesin
True.
 
Richard Terrett
Richard Terrett
there's a pic on wikipedia of plutonium solutions in a bunch of different oxidation states - i bet that was fun to clean up
 
Stack Exchange
Stack Exchange
0
Q: Why is the benzyne triple bond distorted?

ManishearthIn many places I've seen the "extra" bond in benzyne being labelled as $sp^2-sp^2$ overlap or distorted (not parallel) $p\pi-p\pi$ overlap. But I've failed to see why we can't have a normal, parallel $p\pi-p\pi$ overlap. Wikipedia says: In benzyne, however, the p orbitals are distorted to ac...

organic-chemistry molecular-orbitals
 
Aesin
Aesin
12:53 PM
I saw a presentation recently from a Russian group who were using plutonium as a dopant in ceria crystals to make them glow..
Which sounds really neat but I bet the safety precautions are pretty onerous.
 
Richard Terrett
Richard Terrett
@Aesin - to achieve what precisely?
 
Aesin
Aesin
@RichardTerrett: As far as I can tell, mostly just to achieve glowing crystals.
2
 
Richard Terrett
Richard Terrett
@Aesin - Ah, the Cave Johnson approach!
 
Aesin
Aesin
Hmm, I wonder what the concentrations are like in those test tubes - I know actinides are much more strongly coloured than transition metals but still...
Hm, I might be thinking of lanthanides -> actinides rather than TMs -> actinides. The hazards of never actually seeing the compounds you do computational work on...
 
Richard Terrett
Richard Terrett
'I'll be honest, we're just throwing science at the wall here to see what sticks'
 
Aesin
Aesin
1:02 PM
(The answer, of course, being all the different colours of gel.)
 
Richard Terrett
Richard Terrett
The new mars rover has a rather large PuO2 RTG
 
Aesin
Aesin
7.8 g of plutonium -> 2000 Watts of heat. O_o
(This is the future! Where is my nuclear kettle?)
 
Richard Terrett
Richard Terrett
@Aesin - where did you get that figure from?
 
Stack Exchange
Stack Exchange
1:19 PM
0
Q: Why does benzene bend in this reaction?

Manishearth I can see why hapticity changes here, but not why it is necessary for the benzene ring to bend. The resonance energy of benzene is pretty large, and there's no balancing increase in stability elsewhere--unless the decrease of hapticity increases stability, which I doubt (more delocalization=mor...

organic-chemistry redox coordination-compounds organometallic-compounds benzene
 
Aesin
Aesin
(Though I might have misinterpreted the table headings, they're not the clearest.)
 
Richard Terrett
Richard Terrett
@Aesin - I think you missed a kilo-
Damn, I'm trying to plot some calculated MOs for Manish's earlier question on benzene and I can't get anything to work right
molekel only seems to plot one phase, paraview plots both phases but doesn't colour by phase, vesta crashes for some reason
 
Aesin
Aesin
@RichardTerrett: Oh yes, oops...
@RichardTerrett: What's your output format?
 
Richard Terrett
Richard Terrett
1:34 PM
paraview can do volumetric plots of orbitals, which takes a lot of stuffing around but looks gorgeous. of course gorgeous != useful.
gaussian cubefile, generated by orca
 
Aesin
Aesin
I think Avogadro can do those pretty nicely, as long as you don't need f functions.
(Which I guess you won't with a cubefile?)
 
Richard Terrett
Richard Terrett
i'll try that now
 
Aesin
Aesin
(Though I think you'll need to use the "Import File" option from the File menu rather than just the "Open" option - due to the division between the OpenBabel importers and Avogadro's own ones.)
 
Richard Terrett
Richard Terrett
@Aesin - no luck
@Aesin - I think avogadro expects the file to have no blank lines
@Aesin - Having another go in paraview... This looks really neat
@Aesin - MO 16 of benzene i.imgur.com/g5wGA.png
 
Aesin
Aesin
1:49 PM
@RichardTerrett: Hm, fuzzy. As you say, probably not that useful. Especially without the ability to rotate it.
(Though that's older work than the presentation I saw.)
 
F'x
F'x
@RichardTerrett oh, volumetric plot!
shiny shiny shiny
I usually do isosurfaces (with VMD)
 
Richard Terrett
Richard Terrett
@Aesin - thanks for the ref!
 
F'x
F'x
what annoys me most about visualization is that I don't have a single tool that handles both periodic systems + trajectories + varying number of atoms along the trajectory
 
Richard Terrett
Richard Terrett
@Fx - can VMD read cubefiles?
@Fx - I was planning on writing a script to create supercells out of a unit cell optimisation trajectory for visualisation in pymol or molden
 
F'x
F'x
@RichardTerrett yes
 
Richard Terrett
Richard Terrett
1:59 PM
@Fx - Ah cool. Is there a simple way to create a double isosurface in VMD?
or do i have to create two with opposite phases?
 
F'x
F'x
@RichardTerrett two with opposite phases; but that's just two more clicks
 
Richard Terrett
Richard Terrett
I guess so :D
 
F'x
F'x
now, I'm working on a patch for VMD that will enable export to 3D PDF; if I manage that, it'll be totally awesome (if I might say so myself)
 
Richard Terrett
Richard Terrett
@Fx - you're a VMD developer? awesome!
 
F'x
F'x
@RichardTerrett no, I just have my name in the contributors list somewhere, but I'm not a regular
I provided some 5 or 6 patches in total
 
Richard Terrett
Richard Terrett
2:02 PM
Fx - Still awesome
 
Manishearth
Manishearth
VMD=? Veapons of Mass Destruction?
Aah, visual Molecular dynamics :)
 
F'x
F'x
it has a polyhedral representation type, which I contributed
import of OFF file format for surfaces, also
 
Manishearth
Manishearth
Interesting...
 
Richard Terrett
Richard Terrett
My current avatar was done via VMD STL export to blender
 
F'x
F'x
@RichardTerrett that's cool
do you know of a toolchain to create 3D PDFs?
 
Richard Terrett
Richard Terrett
2:04 PM
No
I did notice a 3d pdf rendering option in the VMD menus
Display -> RenderMode -> Acrobat3d
My videocard makes the most disturbing high pitched squeal when I rotate something in VMD
 
F'x
F'x
@RichardTerrett this works very very badly, and only with quite old versions of Acrobat3D (which Adobe has since sold to another company)
 
Richard Terrett
Richard Terrett
@Manishearth - that's the bonding MO of benzene w/ all p orbitals in phase
 
F'x
F'x
@RichardTerrett yep, this has the "carbon is cyan" default VMD look :)
 
Manishearth
Manishearth
@RichardTerrett Aah, nice
 
Richard Terrett
Richard Terrett
@Manishearth - from a spin-restricted RI-BP86/6-311G* calculation
in orca
 
Manishearth
Manishearth
2:12 PM
@RichardTerrett Don't know enough to understand that :/
 
Richard Terrett
Richard Terrett
@Manishearth - relatively lightweight electronic structure calculation
does this count as a publication? do i need a citation?!
 
Manishearth
Manishearth
@RichardTerrett Aah, thanks :)
 
Richard Terrett
Richard Terrett
Anyhow, a key point is that orbital is equally distributed over all of the carbons and only has 2e- in it
 
Manishearth
Manishearth
@RichardTerrett ?? Then what about the others?
That means we have six orbitals---aaand they each have their own quantum numbers, right?
 
Richard Terrett
Richard Terrett
Did you check the wiki page on MO theory?
 
Manishearth
Manishearth
2:17 PM
@RichardTerrett Somewhat.. wait, I'll read it
(one sec, writing up an MSO post)
 
F'x
F'x
@RichardTerrett I will ask SE to give us DOI's for each post on Chemistry, then integration with crossref… I want this in my h-factor!
 
Richard Terrett
Richard Terrett
@Fx - Oh I mean the orca license stipulates that you need to cite the relevant papers when results are published that are obtained with orca
 
Manishearth
Manishearth
@Fx It seems that TP.SE used to register refs with ArXiv and generate trackbacks
 
Richard Terrett
Richard Terrett
interesting
Here we go: Neese, F. ORCA – an ab initio, Density Functional and Semiempirical program package, Version 2.6. University of Bonn, 2008
the name is a pain (not neese's fault) because the current ubuntu screen reader is called orca
and for good measure: Humphrey, W., Dalke, A. and Schulten, K., 'VMD - Visual Molecular Dynamics', J. Molec. Graphics 1996, 14.1, 33-38.
@Manishearth: regarding your benzene-ru-sandwich question
 
Manishearth
Manishearth
@RichardTerrett yep
?
 
Richard Terrett
Richard Terrett
2:26 PM
@Manishearth - you mention you know why the hapticity changes and then say you don't know how the hapticity changes
which is it?
or is it a matter of how != why?
 
Manishearth
Manishearth
@RichardTerrett If the structure is actually bending, then it's obvious why haptivity changes--the delocalization is broken and we get delocalization amongst four only
If, on the the other hand, the bending was just for clarity, then I don't know
edits
Sorry about that :/
 
Richard Terrett
Richard Terrett
The other possibility is that the ring could be tilted
 
Manishearth
Manishearth
@RichardTerrett Hmmm... that makes sense, though I fail to see why it would do that
 
Richard Terrett
Richard Terrett
@Manishearth - because an eta-4, eta-6 arrangement satisfies the 18e- rule
for the reduced species
 
F'x
F'x
@RichardTerrett not the 18-electron rule, but it fills the d orbitals, right?
 
Manishearth
Manishearth
2:34 PM
@RichardTerrett EAN? Hmmm, makes sense
 
Richard Terrett
Richard Terrett
@Fx - I don't understand
@Manishearth - if both rings had the same geometry it would force extra electron density onto the metal which is unfavourable
this is all speculation mind you
 
Manishearth
Manishearth
You can still post speculation if you mark it as such
(Though that may deter others from answering)
But I don't mind :)
 
Richard Terrett
Richard Terrett
I suspect the ring is either tilted or that the degree of bending is fairly small, or a combination of the two
stick diagrams can be very deceptive
especially in inorganic/organometallic chemistry
 
Manishearth
Manishearth
Yeah
If anyone has access to it, here is the ref Wikipedia cited: onlinelibrary.wiley.com/doi/10.1002/anie.197105561/…
 
Richard Terrett
Richard Terrett
Hmph, no ESI, that's unfortunate
 
F'x
F'x
2:41 PM
@RichardTerrett I had forgotten to count the electrons from the bottom aromatic ring :(
/me hides
 
Manishearth
Manishearth
@RichardTerrett ESI ?
 
Richard Terrett
Richard Terrett
electronic supporting information
@Fx - no problem :D
 
Manishearth
Manishearth
Aah. No abstract/pdf/etc. Yeah, I saw that. :/
gtg for an hour
 
F'x
F'x
 
Richard Terrett
Richard Terrett
ooh!
 
F'x
F'x
2:43 PM
so there is something to this drawing
(as an aside: okay, I've gained 85 rep in 5 minutes… someone is like serial-upvoting me!)
 
Richard Terrett
Richard Terrett
I think it's safe to assume aromaticity is broken in the eta-4 ring
Fx - Do you know how the hexamethylbenzene version compares to the unsubstituted one?
 
F'x
F'x
@RichardTerrett it's funny, becase C11-C16 is much shorter, but none of the other C-C bonds are significantly longer
 
Richard Terrett
Richard Terrett
@Fx - it wasn't me
 
F'x
F'x
@RichardTerrett it's aromatic and planar, but I don't know anything more about it
> The second ring is bent about the axis C(12)-C(15). The distance of the Ru from the best plan: through atoms C(12), C(13), C(14), and C(15) (o=0.009A), amounts to 1.73 A. [...] The cyclic conjugation in the ring is thus con- siderably disturbed (see Fig. 1). The bond length C(16) to C(11)of 1.327(10)Ais that of a pure double bond.
back in the days where an Angewandte letter could be one-and-a-half column long
 
Richard Terrett
Richard Terrett
@Fx - most edifying!
 
F'x
F'x
2:50 PM
well, I won't have time to make an answer out of it, but please do!
we need that to be on record :)
also, I wouldn't write answers to coordination chemistry questions, because I'm so bad at it
 
Richard Terrett
Richard Terrett
@Fx - my dream job: being the person who writes the lame puns for the ACIE web table of contents
no offense to the person who does it, i love lame puns
@Fx - well, it's approaching 1am here, so maybe later
@Fx - I had fun writing the z-matrix answer
@Fx - I demonstrated for a tutorial on comp chem a few months ago, constructing z-matrices
it was astonishing
almost every student had their own zany way of doing it
 
F'x
F'x
@RichardTerrett I still remember my first comput chem exam, the first (pen and paper) question was: write a Z matrix for cubane
that was somewhat tedious, just to make sure you didn't forget anything
 
Richard Terrett
Richard Terrett
did it have to have Td symmetry?
 
F'x
F'x
@RichardTerrett cubane is Oh, isn't it?
 
Richard Terrett
Richard Terrett
yeah, my bad
damn
i've been working with inorganic cubanes for so long
those have Td symmetry
 
F'x
F'x
2:59 PM
@RichardTerrett inorganic cubanes?
 
Richard Terrett
Richard Terrett
yeah like Fe4S4
 
F'x
F'x
@RichardTerrett oh fun!
 
Richard Terrett
Richard Terrett
@Fx - like I said earlier, the tyranny of stick diagrams! scidac.gov/BES/BES_OSSLM/reports/images/taylorfig1.jpg
 
Manishearth
Manishearth
@RichardTerrett Inorganic cubane? My new favorite molecule
Aah, my rep has reached a rather nice number :)
 
F'x
F'x
okay, gotta go, talk to you later!
 
Manishearth
Manishearth
3:15 PM
Now I wish this badge existed :P
 
Richard Terrett
Richard Terrett
3:33 PM
@Manishearth - 9 downvotes is a bit rough
must be all the Hexakosioihexekontahexaphobes coming out of the woodwork
 
F'x
F'x
@RichardTerrett that's the nature of voting on meta: you don't downvote because the question/proposal is bad, but because you are against it
 
Richard Terrett
Richard Terrett
@Fx - when I was much younger and more impressionable I was handed a bunch of leaflets from some dispensationalist group telling me that UPC barcodes were the mark of the beast
cue barcode conspiracy phobia ("they're everywhere!")
 
F'x
F'x
Dispensationalism
Dispensationalism is a nineteenth-century evangelical, futurist, biblical interpretation that foresees a series of "dispensations" or periods in history in which God relates to human beings in different ways under different Biblical covenants. As a system, dispensationalism is rooted in the writings of John Nelson Darby (1800–1882) and the Brethren Movement. The theology of dispensationalism consists of a distinctive eschatological "end times" perspective, as all dispensationalists hold to premillennialism and most hold to a pretribulation rapture. Dispensationalists believe that the...
hum, I've read that somewhat, and still don't understand what it's talking about :)
 
Manishearth
Manishearth
@RichardTerrett I got one unupvote, not nine downvotes :)
Oh, the meta quesntion
 
Richard Terrett
Richard Terrett
yeah
@Fx - tbh I don't know what they were beyond apocalyptic christian
the UPC barcode thing is still going around, I think it was on skeptics.se recently
 
Manishearth
Manishearth
3:42 PM
@fx I don't understand it either :p
@Rich btw, you can't ping fx that way in chat
 
Richard Terrett
Richard Terrett
hmm?
 
Manishearth
Manishearth
5
Q: Cannot @reply users with an apostrophe in their username

Manishearth Slightly related: Users Search box doesn't find names with an apostrophe ' If a user has an apostrophe in their username, while typing out an @reply, the system suggests a username without the apostrophe. Which is fine, but in both cases, the user does not get notified I know that @...

bug chat
 
Richard Terrett
Richard Terrett
oh, thanks
 
Manishearth
Manishearth
You must use message replies
Since Fx is our most active user we may need a featured metapost to warn everyone :p
 
Richard Terrett
Richard Terrett
Indeed! F'x is really kicking arse in the questions and answers stakes
 
Manishearth
Manishearth
3:49 PM
By the way, @rich, I'll read your answer a bit later, current ly mathjax is broken on my phone (Shows [math processing error], this bug comes and goes)
 
Richard Terrett
Richard Terrett
ok
 
Manishearth
Manishearth
Yep, probably double the rep of the second highest
 
Richard Terrett
Richard Terrett
I think it's correct
 
Manishearth
Manishearth
/checks
 
F'x
F'x
@RichardTerrett I'm trying to slow down because 1. I should focus on my work! and 2. others should get to write answers to the easy questions too :)
 
Manishearth
Manishearth
3:50 PM
Oh, I am the second highest *blushes*
 
Richard Terrett
Richard Terrett
@Fx How do you get the nice wikipedia abstract in the chat message?
 
F'x
F'x
@RichardTerrett just paste a link as sole content of a message, and if it is from a well-known site, the chat engine will include an excerpt
 
Richard Terrett
Richard Terrett
ahh, thanks
 
F'x
F'x
"well-know sites" include wikipedia, xkcd and other works of reference
 
Manishearth
Manishearth
Its called oneboxing
Also posts, comments, and chat messages
 
Richard Terrett
Richard Terrett
3:53 PM
@Fx I like the way you phrased that
'Important transnational organisations such as the united nations, reddit, etc.'
 
Manishearth
Manishearth
@rich regarding your answer, what happens to the other four electrons?
 
Richard Terrett
Richard Terrett
they're in different MOs
 
F'x
F'x
@RichardTerrett English is not my mother tongue, so I am never sure how much my attempts at humor get through to people :)
 
Manishearth
Manishearth
Are they in similar MO rbitals?
Or different MOs? (as in type)
 
Richard Terrett
Richard Terrett
@Manishearth - yes but they have different shapes due to being composed of different additive or subtractive combinations of p_z orbitals
@Fx No, it's good, very deadpan :D
@Manishearth - gimme a moment I'll render up the HOMO level
 
Manishearth
Manishearth
3:58 PM
@rich interesting.
@rich oh cool I'll wait for the pretty pictures :)
@fx if it makes you feel better, my attempts at humor in French fail miserably as well (I use it a bit with my friends to keep in practice)
:p
 
F'x
F'x
@RichardTerrett I love English-style deadpan irony :)
 
Richard Terrett
Richard Terrett
@Manishearth - tada!
 
F'x
F'x
@Manishearth okay, you can practice with CHM and me :)
it's not as nice as Richard's, but you have all the levels there
 
Aesin
Aesin
All hail the Huckel theory.
 
F'x
F'x
(it's not mine, and it's based on Hückel's model)
 
Richard Terrett
Richard Terrett
4:04 PM
@Manishearth - that's the highest occupied MO - two antiphase sets of 3 pz orbitals
 
F'x
F'x
@Aesin /me bows
 
Richard Terrett
Richard Terrett
@Manishearth - the top two MOs are quasidegenerate, it seems
 
F'x
F'x
@RichardTerrett more than quasidegenerate, they are really degenerate, aren't they?
 
Richard Terrett
Richard Terrett
I'm not sure, in my calculation there's a slight difference but that may be because my calculation wasn't formally D6h
 
F'x
F'x
they have E(2u) symmetry
@RichardTerrett yeah, that would be it
 
Richard Terrett
Richard Terrett
4:07 PM
in that case yes
 
F'x
F'x
I'll just highlight that I'm not that proficient with the symmetry classes of D6h… I just happened to make a benzene calculation two hours ago for Mannis' benzyne question :)
 
Richard Terrett
Richard Terrett
yeah the difference in my calc is vanishingly small
 
Manishearth
Manishearth
@rich and fx oh wow thanks!
 
Aesin
Aesin
I am kind of tempted to run the two Ruthenium optimisations.
 
Richard Terrett
Richard Terrett
I tried
 
F'x
F'x
4:08 PM
sometimes, I wish we could have a basic multiplatform open source quantum-chem software, so that people with minimal knowledge of QChem would be able to visualize orbitals for their simple systems
 
Richard Terrett
Richard Terrett
no SCF convergence
 
F'x
F'x
@Aesin I was too, but I don't have any Ru basis set around
 
Richard Terrett
Richard Terrett
@Fx You use qchem?
 
Aesin
Aesin
@F'x: Jmol?
 
F'x
F'x
@RichardTerrett CRYSTAL
@Aesin Jmol does calculations too?
 
Aesin
Aesin
4:09 PM
Oh, no.
 
Richard Terrett
Richard Terrett
@Fx Oh, so not the program called 'Q-Chem'?
 
Manishearth
Manishearth
@rich you may want to add the pretty pictures to the post (I'd do it myself, but I can't easily do it from mobile)
 
F'x
F'x
@RichardTerrett no, I meant quantum chem :)
 
Richard Terrett
Richard Terrett
ah right
 
F'x
F'x
so, anyone knows what compound other than Ru could be used instead?
I was tempted to run it with Fe, just to check :)
 
Manishearth
Manishearth
4:12 PM
Cr has a similar complex
 
Richard Terrett
Richard Terrett
I was able to get it to run in orca using the tzvp basis, but i couldn't get SCF convergence
 
Manishearth
Manishearth
But I don't think it works there. Its not gr VII
 
Aesin
Aesin
The easiest way to get something like that would probably be to hook something like the Python QM package up to Avogadro as a plugin.
 
Manishearth
Manishearth
/me is overawed by the discussiin on chem softwares :p
 
Richard Terrett
Richard Terrett
@Fx Do you know why everything in VMD is antialiased except for the cpk spheres?
 
Aesin
Aesin
4:14 PM
(PyQuante is the one I'm thinking of, but no doubt there are others.)
 
F'x
F'x
@RichardTerrett in OpenGL display?
 
Richard Terrett
Richard Terrett
it's making my OCD twitch :D
yeah
 
F'x
F'x
for me, nothing is antialiased :)
do you use the GLSL rendermode?
 
Richard Terrett
Richard Terrett
yeah
ah, that does it
but the regular rendermode looks nowhere as nice
 
F'x
F'x
well, in GLSL, spheres are treated separately from all other graphic elements, because they use shaders while others (like cylinders) use polygonal approximation
 
Richard Terrett
Richard Terrett
4:15 PM
oh!
you learn something new every day
@Fx Have you seen the way molden software-renders spheres and cylinders?
 
F'x
F'x
also, I have a setup with 120 Hz screen and stereo glasses at work, and VMD in quad-buffered stereo display is awesome
 
Richard Terrett
Richard Terrett
:(
 
F'x
F'x
@RichardTerrett I saw that 10 years ago, when molden was only like "very old software" :)
 
Richard Terrett
Richard Terrett
here i am trying to scrounge a pair of anaglyph glasses...
 
F'x
F'x
@RichardTerrett anaglyph? oh, the red/blue…
 
Richard Terrett
Richard Terrett
4:18 PM
yeah
 
F'x
F'x
 
Richard Terrett
Richard Terrett
molden will never die
 
F'x
F'x
admittedly, the secretary in the lab was a bit surprised when she received the package, because it's marketed as "gaming" stuff, with elves and sparingly-dressed lady adventurers on the box :)
but I manage to convince everyone that I was using it for Real Science
(and I actually haven't found time in 3 years to use it for a game… maybe the students or post-doc did, however)
 
Richard Terrett
Richard Terrett
i was trying to convince my supervisor to upgrade our video cards
we're using some kind of intel integrated
 
F'x
F'x
@RichardTerrett I had to buy a $1k graphics card to go with it
 
Richard Terrett
Richard Terrett
4:20 PM
they're shockingly slow for ADF-GUI
i was able to get a 26% performance increase by dropping a bottom of the line HTPC card in
 
F'x
F'x
@RichardTerrett well, talking of slow, at my previous place I had a one-screen two-computers setup, in order to have a SGI MIPS/Irix box with an old Cerius2 license on it
 
Richard Terrett
Richard Terrett
with a $100 card i could make the systems 5 times as fast
 
Aesin
Aesin
ADF-GUI is rather slow for most things.
 
Richard Terrett
Richard Terrett
see i can't read SGI without thinking 'computer archaeology'
 
Aesin
Aesin
(IME)
(But then I use it over an X connection.)
 
F'x
F'x
4:23 PM
@RichardTerrett well, I bought it second-hand at the beginning of my post-doc, 4 years ago
@Aesin do you use X11 forwarding?
 
Richard Terrett
Richard Terrett
@Aesin - me too
 
F'x
F'x
if you use X forwarding, you could try NX-based solutions
for some apps, it makes the UI much smoother; the idea is that it renders stuff and sends the compressed bitmap over the connexion, rather than allowing X requests to be sent back and forth
especially on asymmetric links (ADSL-like), it's much better that direct X forwarding
 
Aesin
Aesin
@F'x: Sounds neat, I'll take a look.
Rather VNC-like.
 
F'x
F'x
@Aesin yes, but with tighter integration IIUC
it's a X11 module, I think, while VNC spawns its own X server
anyway, I'm going now; nice to talk to y'all!
 
Richard Terrett
Richard Terrett
ok
 
Manishearth
Manishearth
4:28 PM
@fx same here, cya around!
 
Manishearth
Manishearth
4:47 PM
@people how on-topic would a notation question be?
 
Aesin
Aesin
Post it anyway, then people can argue about whether it's on topic or not. :)
 
Manishearth
Manishearth
A friend of mine (with an account) has a question about the origin of the notation t_{2g} and e_g , which I discouraged but told her to ask anyway
@aesin I told her to ask anyway for the same reason :)
Arguing is fun!
 
Manishearth
Manishearth
5:08 PM
K, I've got to turn in now.. Cya guys!
 
F'x
F'x
5:25 PM
@Manishearth would love to see that one (and its answers)
 
 
2 hours later…
F'x
F'x
7:33 PM
All hands on deck… we should move into public beta soon (next day or so)
 

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