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- - By Felix Kling (Gold) Date 2016-02-17 19:03 Upvotes 1
Hi everyone! I defended my thesis two weeks ago and got my certificate yesterday, so I'm Dr. Felix Kling now ;-)
My thesis is about diffusion and structure formation of molecules on calcite(104) in ultra-high vacuum probed with NC-AFM. Since the work isn't published yet (neither parts in journals not the whole thesis), I can't tell you all the details, but if you are interested, I'll write if parts of it or the complete thesis are published :-)
Parent - - By user923005 (****) Date 2016-02-17 19:09
When the thesis is published, I would like to get a link to it.
Parent - By Felix Kling (Gold) Date 2016-02-17 22:06
OK, I'll post it :-) Will take some time, more than 4 papers will be written with material from the thesis, so probably in 1-2 years it's public :-). However, I'll post the papers when they are ready to create some excitement ;-)
Parent - - By Felix Kling (Gold) Date 2018-08-22 09:52
one of the "highlights": first time imaging of the molecular self-assembly process (not "just" the result)
Parent - - By gsgs (***) Date 2018-08-22 12:51
where is the molecule
Parent - - By Felix Kling (Gold) Date 2018-08-23 09:45 Edited 2018-08-23 10:00
the bright stuff including the blobs that sometimes move (then marked with crircle and arrow indicating the location in the next image) are the molecules, the green background is the surface
Parent - - By gsgs (***) Date 2018-08-27 13:13

IMO better (or additionally) for the laymen just show the endpositions
and the arrows as paths in one picture

or without the confusing circles and bigger arrowheads instead

disappearing circle+arrow = stationary, no movement
molecules are not created/assembled or disappear ?

ahh, now I see, 8 pictures marked 1,..,8 , maybe a pause between 8 and 1 would also be useful

I still don't know what happens in the 2 rectangles
Parent - - By Felix Kling (Gold) Date 2018-08-27 14:11 Edited 2018-08-27 14:13
well, OK, one could improve that graphic, but on the other hand it is good enough for the forum or Wikipedia :-) .

What you see with nucleation and growth is that the particles form stripes and append to stripes so that the stripes you see in the image are created and become larger. If you wait for some more time, all molecules are part of stripes and you only see the striped structure.

The tricky part is to slow down the molecules (low temperature) so that they just start to form stripes. This is actually "very" tricky as this is some exponential stuff where a few kelvin change everything :-) (and coverage should be neither too large nor too small...).
Parent - - By gsgs (***) Date 2018-08-28 06:05
ahh again.

Now I understand.
These short white stripes are growing chains of molecules !
When you know it, it probably seems all so clear and obvious,
but not when I see it the first time without any experience in the subject.
Maybe all the others here understood it or didn't dare to ask for 2 years.

Why are all the stripes parallel ?
One "explosion" above growth triangle ?
How long are the longest stripes in the picture in meters ?
Parent - By Felix Kling (Gold) Date 2018-08-28 18:42
The calcite surface has one of its main directions (due to its symmetry) in the direcitons of the stripes, so the stripes are only "stable" if they form in that direction due to molecule-surface interactions. The length of the longest stripes is roughly 8 nm. The "explosion" may be some impurities on the surface that look different under the AFM. But we will never know what exactly it is :-) .
Parent - By user923005 (****) Date 2018-08-22 18:09
Thanks.  I downloaded a copy.  I will probably read it tonight.
Parent - - By Labyrinth (*****) Date 2018-08-22 21:22
So cool!! Jealous. I will read through it even though I will probably understand little : )
Parent - - By Felix Kling (Gold) Date 2018-08-23 09:48 Edited 2018-08-23 09:56 Upvotes 1
well, you should get the idea what I was doing, in principle a know-nothing could perform the measurements (but they take a lot of time) and the evaluation is basically reinventing image stabilisation in a poor way plus some basic statistics that look complicated ;-) (OK, it may be a little more complicated than that :-D )
Parent - - By Labyrinth (*****) Date 2018-08-23 23:46
Any idea on how one might make cubic boron arsenide nanocrystals? : )
Parent - By Felix Kling (Gold) Date 2018-08-24 10:15
I'm a physico-chemist, so I neither now much about physics nor chemistry, what do you expect? :-)
Parent - - By Lukas Cimiotti (Bronze) Date 2016-02-17 19:30
Herzlichen Glückwunsch Felix. :smile:
Parent - By Felix Kling (Gold) Date 2016-02-17 22:03
Danke :-)

Auf dem Photo sieht man mich übrigens nach dem obligatorischen Besteigen der Pferdeskulptur auf dem Campus nach der Verteidigung ;-)
Parent - - By turbojuice1122 (Gold) Date 2016-02-17 20:15
Congratulations, Felix!
Parent - By Felix Kling (Gold) Date 2016-02-17 22:04
thanks :-)
Parent - - By Venator (Silver) Date 2016-02-17 20:15
Parent - By Felix Kling (Gold) Date 2016-02-17 22:07
thanks, Jeroen :-)
Parent - - By Labyrinth (*****) Date 2016-02-18 02:23
Awesome! Congrats!

Any pretty pictures from the NC-AFM?
Parent - - By Felix Kling (Gold) Date 2016-02-18 09:15 Edited 2016-02-18 09:23 Upvotes 2
thank you :-)

here's an image while cooling the microscope stage with liquid helium
Parent - - By Labyrinth (*****) Date 2016-02-18 11:48
I was thinking of pictures taken with the NC-AFM not of the NC-AFM, but this is also really cool :-)

Always amazes me how 'ad hoc' those things tend to look. More like something someone assembled in their garage than a state of the art scientific instrument, but looks can be deceiving!
Parent - - By Felix Kling (Gold) Date 2016-02-18 17:34 Edited 2016-02-18 17:40
Ah, sorry, of course :-) here's an image of an interesting molecule. Can't tell any details yet ;-)

Btw., the instrument is an Omicron VT-AFM XA, so it's a commercial system made by a company from Taunusstein, Germany
Parent - - By Labyrinth (*****) Date 2016-02-18 21:27

>here's an image of an interesting molecule. Can't tell any details yet ;-)

Cool! What's the magnification on that, or rather how far across is it from one side of the image to the other?

>Btw., the instrument is an Omicron VT-AFM XA, so it's a commercial system made by a company from Taunusstein, Germany

Not something you can order from Newegg though ;-)

Very cool. The rivets give it that steampunk look though, like the inside of a vintage submarine.
Parent - - By Felix Kling (Gold) Date 2016-02-20 06:24 Edited 2016-02-20 06:26
this is something like 35*35 nm², so molecular resolution. Note that these structures self-assemble, which is quite fascinating :-)

the submarine comparison is quite fair, it's basically the same concept (little pressure inside, large outside)
Parent - - By Labyrinth (*****) Date 2016-02-20 11:36
So that one in the middle would about 7 nm in length? Yeesh. Even a Cesium atom is only 0.5 nm across. There appears to be two 'peaks', like two atoms lined up together in a row. I wonder what they could be? How well can you control their self-assembly? So many questions..
Parent - By Felix Kling (Gold) Date 2016-02-20 16:50 Edited 2016-02-20 16:57
These are small molecules, the size of one molecule in the image depends on the interaction with the tip and is usually a bit larger depending on the tip apex (~1-2 nm). We can't control the self-assembly that much, it is more like try and error, although we can change molecule properties by molecule functionalisation. Still, we are far away from being able to tell for sure what structure a certain molecule will form.
Parent - - By turbojuice1122 (Gold) Date 2016-02-20 15:59
The self-assembly is very interesting--could this potentially lead to self-replication, given the correct conditions?
Parent - - By Felix Kling (Gold) Date 2016-02-20 16:54
Basically molecular self-assembly happens due to the interaction between single molecules that leads to interesting structures. However, self-replication and so on is usually something connected to DNA and so on and requires much more complex molecules. What we study is on a basic level, although this is indeed one of the principles that are key for understanding the origin of life.
Parent - - By RFK (Gold) Date 2016-02-20 17:40
So what is your promising end to all this? Do Pharmacological research using multi-stranded DNA and RNA microarrays (like I even know what it is I'm referencing) to find new drugs?
Parent - By Felix Kling (Gold) Date 2016-02-20 18:48
I'm not sure what "promising end" means, but I guess it means what I will do: Well, I'm taking a break at the moment and won't continue with this scientific stuff. Don't know what I do after the break :-)
If it's about the practical use of what I did in my thesis: This is not about application, it is more fundamental research. Can't imagine any use for it ;-)
Parent - - By Geomusic (*****) Date 2016-02-21 06:39 Edited 2016-02-21 06:57
If there was a way to make a soap bubble inside another filling the inside space exactly so that each bubble inside the next completely filled it without merging into any proceeding bubble boundries how many bubbles could I make if I started with a bubble 1 cm/3 diameter and ended with a bubble 1 nm/3 in diameter? Also on a side note what would be the pressure surrounding this 1nm/3 bubble?
Parent - - By Labyrinth (*****) Date 2016-02-21 12:36
Why would a diameter be cubic? Or even square for that matter? Did you mean volume?
Parent - - By Geomusic (*****) Date 2016-02-21 16:54
Volume within a sphere
Parent - - By Labyrinth (*****) Date 2016-02-22 02:02
This question has a lot of problems.

For one, soap bubble walls don't get under 1 nm, the lower bound that I've seen is 10 nm. If I lower the separation between walls to fit in more bubbles to some very small number say 1 nm and keep the temperature constant, the pressure on the inside of its parent bubble becomes enormous, far more than enough to burst the bubble. What's more is that the necessary pressure for the inside bubble would have to be enormous as well, and thus the walls would experience an enormous amount of pressure on both sides, squeezing them until they popped for sure.

If the bubble were to expand it would have to be known by how much and the pressure of the inner bubbles calculated accordingly. This quickly turns into nightmare calculations, and even so you'd never get walls that close without breaking the parent bubble.

If you just want some pure mathematical treatment, how many bubbles fit with walls of say 10 nm, and separated by 1 nm, then 563954 bubbles would fit inside a 1 cubic centimeter bubble volume, leaving a remaining volume of 5575.28 cubic nm, a long way from the 1 cubic nanometer figure.

The pressure could probably be calculated with a stipulation like, the inside/outside pressures of any bubble increase by whatever is required to maintain the bubble's volume, and the temperature remains constant. That would be quite magic, but would allow some function to be made where n bubbles could just be plugged in.

I guess I'm just not sure what the question is supposed to be asking. Where did this question come from? Why did it say 1 cm^3 as a 'diameter' at first? What is the context?
Parent - - By Geomusic (*****) Date 2016-02-29 03:53
Just my own imagination. It was more of a thought experiment gone wrong I guesx
Parent - - By Labyrinth (*****) Date 2016-02-29 08:45
You have quite the imagination! With a few modifications that becomes a reasonably contemplatable but still nightmare problem that would keep some forum like physicsoverflow going for weeks.

Starts to feel like navier-stokes equations or something. I was afraid you had pulled it from a putnam exam or knew there was some devilish trick to it.
Parent - By Geomusic (*****) Date 2016-03-24 02:53
Are you a Mathematician?
Parent - By mjlef (***) Date 2016-07-17 19:44
I knew it!  Felix build the worlds most accurate still. Best moonshine ever!
Parent - By The Wizard (***) Date 2018-08-26 22:34
Many congratulations Felix I am late as ever, loved the pic with liquid helium :grin:

Parent - - By Walter Koroljow Date 2016-02-18 12:32
Parent - By Felix Kling (Gold) Date 2016-02-18 17:38
thanks :-)
Parent - - By irulats (****) Date 2016-02-19 00:02
Congratulations! :cool:
Parent - By Felix Kling (Gold) Date 2016-02-20 06:22
thx :-)
Parent - - By InspectorGadget (*****) Date 2016-02-29 11:59
Congrats Dr Felix Kling.
Parent - By Felix Kling (Gold) Date 2016-02-29 15:16
thanks :-)
- - By Felix Kling (Gold) Date 2016-02-17 22:12 Upvotes 1
Some more images (receiving the hat and kissing the Gutenberg statue (part of the ceremony after the defense))
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