A visit from Michigan

Last Sunday I enjoyed a visit from Troy, MI. That's right, even though it is still my first trip outside the borders of Good Old Europe, I am having friends in the US, which don't live in Chicago. The ones I am talking about here I met in Berlin. Stefan used to be a PhD student colleague at the Fritz Haber Institute. Since he is married to an American (Liz), he has made his way to the US even before me. Lucky him was offered a position at a company called RHK, which manufactures scanning tunneling microscopes. Since Stefan actually built his own machine as part of his research, for which RHK electronics were used, he is very familiar with this equipment. When he attended a scientific meeting in Berlin, the people from RHK approached him with a job offer, which he eventually accepted. I am very happy for him and his family, because it seems that they are enjoying themselves very much in Michigan. Stefan and I are really good friends, and so I was very pleased when he announced that his wife, his two sons Max(imilian) and Alex(ander) (guess why I call them the "X-men" ...), and himself would be in town for the weekend. And despite their tight schedule they made it happen to meet me on the way home. Yay! While Liz was watching over the little ones, Stefan and I had a really good chat, just like back home. Of course it was all too short, but I enjoyed their visit very much, and I am planning (among other things) to repay the favor before going back to Germany for good. - As you may have noticed, Stefan and Liz named their (second) son Alexander, just like me. While they probably didn't name him after me, they didn't have any objections that I am their son's namesake, which makes me proud, you bet!

Scientists actually

Quite a while ago I have been requested to post some information about my coworkers, Jing and Homa. As you have probably already guessed by now, these are the two charming ladies on the picture. Jing (to the left) is from China, and Homa is an Iranian. While Chinese PhD students are quite common in the US, Iranians are certainly not. I have to admit that when I first met Homa I was very surprised that Iranians are actually allowed to enter the United States, given the long-term bad relationship between these two countries. Fortunately my idea was wrong, because it has turned out that graduates from Tehran university are highly skilled. According to Homa her domestic school should be ranked among the best universities on this planet. While there may (or may not) be a good deal of patriotism in her statement, I must admit that she had undergone a very solid training before joining forces with me. - Now, it would be unfair to praise one student and to leave the other one completely out. Jing has recently been working on a new sample holder for our microscope. This will allow us to do experiments at low temperature (i.e., when the sample is cooled by liquid nitrogen to -196°C or -321°F). Hopefully this will increase our resolution dramatically. (It's the little thing that Homa is holding in her hand, by the way - but no closer looks allowed, as it is top secret!) Jing deserves a strong commendation for her efforts. As you can see, I am very much blessed by being allowed to collaborate with these girls. Even more so, as they are both good company. - You may ask what my job is, if the girls are so talented. Well, that's an easy one: I'm the photographer ...

Science actually

Since it takes me a little longer sometimes to post something new here, I have decided to explain you what I am doing when I am not blogging. I do science. I assume the readers of this blog knew that already pretty much. But actually I am doing pretty science. What does that mean? It means I do measurements that generate very pretty images. But let's start from the top.
I am a chemist, holding the degree of Diplomchemiker from TU Kaiserslautern. I finished my undergraduate studies with a diploma thesis, which is roughly equivalent to a Master's thesis. The Diplom used to be the one and only degree to finish undergraduate studies, while now Bachelor's and Master's degrees can be obtained all across Europe. In the course of this so-called Bologna process the German Diplom has been as good as abandonned. Yet I have such a degree, and since I got it only in 2004, you can tell that I am one of the last students to get one. - The Diplomarbeit, as the final thesis is called in German, was meant to be the project in which the student specializes on one of the sub-fields of chemistry, such as Organic Chemistry, Inorganic Chemistry, or Physical Chemistry, to name but a few. As for myself, I chose Physical Chemistry, because I enjoy doing measurements more than synthesis. A physical chemist is, generally speaking, someone who measures the physical properties of a chemical compound (and of atoms and molecules), or follows chemical reactions by physical means. Let me explain that a little further. In chemical reactions we have reactants and products. The reaction converts the former into the latter. Since they are different molecules, they must differ in some physical property. By following this property (if possible) over time, we can determine conversion rates and other important quantities.
After graduating from TU Kaiserslautern, scarse funding (and poor scientific advising) drove me out of town - which ended up being one of the most fortunate things that have happened so far in my life. I was accepted to become a doctoral student at the famous Fritz Haber Institute in Berlin. It turned out to be a great opportunity for me, as not only I learned an incredible lot about science, but I can now also state that a Nobel prize was awarded to someone while I was actually working at the same institution and in the same field. - It is that field that I would like to introduce now.
As mentioned above, I am a physical chemist. However, this describes my approach to science rather than a field of expertise. When I joined the Fritz Haber Institute (more precisely: the Department of Chemical Physics), I began to specialize in the field of catalysis. That is ironic, as catalysis was the genuine topic of Technical Chemistry at TU Kaiserslautern, and I had never taken any classes related to that. That is because I like fundamental research better than the applied one - but that is exactly how research is done in that place in Berlin.
If you think of a catalyst, you might actually think of an automotive catalyst in the first place. While this is certainly an important and interesting system, catalysts can be applied to vastly more than just cars. By definition a catalyst modifies the energy barrier between the reactants and the products in a chemical reaction, which it does by offering an alternative route. Thus you do not need to spend ("waste") as much energy to surpass the barrier, if you choose the proper catalyst. (If the barrier is even higher than without the catalyst, then that is a so-called 'inhibitor".) - However, and now we finally plunge into my actual work, industral catalysts are highly complex systems that are difficult to study by means of fundamental research. In order to tweak and improve catalysts, we need to understand them as deeply as possible. In terms of fundamental research, this is called "at the atomic level"; i.e., we would like to know the exact location and function of all atoms involved in a catalyzed reaction.
To that end it is beneficial to replace the indusrial catalyst of interest by an appropriate model with reduced complexity. That model should image key features of the structure found in an idustrial catalyst (typically so-called "nanoparticles" dispersed on a "support"), while at the same time it facilitates fundamental studies. The trick is of course that we use the same materials in the models as can be found in a real system (yet often not all of them, again for the sake of simplicity).
While I would like to spare you from outlining the preparation of the models, I would like to dwell on their investigation now. Intrinsically physical chemists will use physical means for their studies. There is more than a handful of different methods, but I deem Scanning Tunneling Microscopy (STM) to be the most demonstrative. One thing I have not mentioned thus far is that the model catalysts I focus on are "heterogeneous". That means they are solids, while the reactans and products are gaseous. Therefore, for a reaction to take place, all parties involved have to come close to each other in the first place. "Close" in this case means that the gas or gases will have to adsorb on the surface of the catalyst. As a doctoral student I (mostly) studied the fate of adsorbates by a technique called Reflection Adsorption InfraRed Spectroscopy (RAIRS), but in order to obtain a complete picture, one has of course to investigate the catalytically active surface as well. That is what STM is there for. Given that surface fulfills certain conditions, STM will image it "on the atomic level", which we postulated to be desirable at the outset of this entry. In simple words, it means that images obtained by STM ideally possess a magnification large enough to even make atoms visible. In that case we can also see the structure of the arrangement of the atoms with respect to each other (the so-called lattice), and the size and relative position of nanoparticles, if they should be present. This structural information can then be correlated to observed reactivity phenomena, and hopefully we can learn how modifying the surface structure will improve the reactivity.
It should also be mentioned that STM is not only good for catalytic studies; it is also capable of moving so-called adatoms (atoms sitting on top of the surface) around. This has been impressively demonstrated by some scientists that have formed Chinese characters from atoms. This is possible because STM is on one hand a "microscope", but on the other hand it does not rely on a combination of magnifying glasses, as traditional microscopes do. Instead, it exploits the so-called "tunneling effect", which belongs to the realm of quantum mechanics. Again I would like to spare you from the details, but essentially it means that we get a current going from a very sharp and thin tip to the surface (or vice versa), even though the two are not touching each other, and hence the electric circuit seems to be interrupted. Yet the tunneling effect allows for closing it despite the lack of direct contact. - Some additional electronic devices make sure that this tunneling current remains the same. Should the tip, which is moving across the surface as indicated in the figure above, encounter a protrusion (or any other change in the local surface), it will compensate for that by backing off accordingly, as the protrusion will lead to a higher current. Hence, the electronics act as a feedback control for the tip, and the compensation motions of the tip are recorded and combined to give an image of the surface. - On the other hand, the tip can also be used to push adatoms around and reposition them as outlined above.
This may sound very complicated, but in most cases I do not touch the physical basis of STM, but I just use it to get some nice images, which will hopefully allow me to better understand the structure/reactivity of a given catalyst. Learning the ropes of using my current machine is most likely much easier than it seems.

"Irish today, hungover tomorrow!"

I haven't updated this blog in a while, so here we go: on past Saturday Chicago hosted the St. Patrick's Day Parade, where the Irish heritage of some (many?) Chicagoans is celebrated. As you would expect, many people were clad in green, and there were leprechaun and shamrock symbols all over the place. My favorite t-shirt phrase is "Kiss me, I'm Irish" (seen on various people who have definitely only very limited Irish ties, if any). Yet more truth lies in "Irish today, hungover tomorrow", as this event is mostly about drinking; even if you are "very little" Irish. - Unfortunately I missed the river being dyed green, as it was done only after the parade. But I've seen pictures, and yes, GREEN it was!
Otherwise there is currently not much to tell. Work is okay, but not progressing as fast as I had hoped. In the upcoming two weeks, I will support my (Chinese) colleague Jing by doing the late shift in the lab. Everyone is invited to keep their fingers crossed, because some nice data would come in handy ... yes, I know, when is it that it would not?
Finally there was a first taste of the warmer seasons. Today is being the hottest day of the year so far (72°F, or 22°C). I saw people in t-shirts and shorts, and I wished I had been one of them. Fare you well, bitter cold!

Atavisms of Acetic Acid

As you all know, I am a chemist. I spent quite some time on studying the art of modyfing matter. What may be unbeknownst to at least a few of you is that I like to study languages as well. What I mean is that I of course enjoy expressing myself in a foreign idiom, but my interest goes well beyond that. I have been intrigued for a long time by the relationship (as well as the lack thereof) between the languages I am familiar with. That is why I so much enjoyed reading an article on the relationship between German and English. Please go ahead and read it for yourself here (in English). More specifically, it is about how native speakers of English are amused by German words. English, due to its history, is a hybrid of a Germanic root, to which Latin and French influences were added over the course of time. Now, that is not breaking news, but as a consequence speakers of English are equipped with a lot of synonyms. As it is common with synonyms, they mean the same thing, but as they are still different words, they are not fully identical. Typically the word of Romance origin is more sophisticated than its Germanic counterpart. I'd like to mention that on the other hand I'm stunned by how the grammar of German and Latin alike are highly regulatory for the use of verbs ("conjugation"; e.g., ich esse, du isst etc.), but English as the hybrid of both is not (I eat, you eat etc.). Now, the source of humour for English native speakers comes from the fact that German does not makes use as extensively of Romance words as English. Thus a concept or an idea that is actually sophisticated and would call for a Romance word is likely to be expressed by a Germanic one in German. The said article presents hydrogen as an example (a good one, in my opinion). Although it is actually Greek and not Latin, it is very illustrative. Literally it means "water maker", as anything hydro- is connected with water, and -gen is an abbreviated form of to generate. In German, however, hydrogen is called Wasserstoff. Due to its homophony with "water stuff", it makes a joke. The homophony is somewhat misleading, as Stoff and stuff are not exactly identical. While they are obviously connected etymologically, Stoff can mean cloth as well as matter, while stuff is a rather casual, if not derogatory word for item. In a more abstract way, the two words are of course still related, as an item that is not further specified is essentially just ... matter.
This is as far as the article goes. I would like to add that not only a misperceived level of elaboration may be a source of humour, but generally any example where two originally identical languages have diverged. A favorite example of mine is the German word Geist, which must be case-sensitively translated as ghost, mind, or spirit, respectively. But in essence a ghost is just a disembodied mind.
A better punchline, however, is the German expression for standing in line, which literally means standing in a snake (imagine the line beig so long that it meanders like a snake). Another funny example stems from a personal experience of mine. A few years ago I joined my then-colleague (now-still-friend) Neetha from the U.S., who was at the time living and working in Berlin, for a night out, along with her husband and some of his colleagues. At some point we were discussing a topic that I have forgotten now, but I do remember this reply of mine, "I am too phlegmatic for that". Neetha accused me of using big words, as she did not understand what I was saying. Indeed, the word "phlegmatic" is of Greek origin, meaning literally covered in "slime" or "saliva". Hence the English connotation of "phlegmatic": sick. Someone who is phlegmatic has their nose full of snot and is suffering from a cold. The German connotation, however, has shifted a bit: a sick person has dampened spirits, and in German "phlegmatic" ("phlegmatisch") denotes someone who is too laid-back to be upset or excited.
Since at the outset I stressed on the fact that I am a chemist, I would like to conclude with another chemical example. Similar to hydrogen/Wasserstoff, oxygen is called Sauerstoff in German. Both speakers of English and German will immediately recognize the root "sauer", or "sour". It reflects the (later falsified) view that oxygen be necessary in molecules of acidic compounds. Given this it is quite ironic that one modern-day definition of acids relies on the presence and exchange of hydrogen atoms, our previously discussed example. (Nevertheless, oxygen-bonded hydrogen atoms are particularly easily exchanged, so there was at least some truth to it.) - Obviously a thing called acid in English is called Säure in German. While the German word relies on the flavor as such, the English word is derived from the Latin word for vinegar, acetum. Conceptually, this means acids are perceived as the essence of vinegar. As really the reverse is true (the essence of vinegar is one acid), vinegar essence was later specifiec as acetic acid, literally vinegaric vinegar essence (Essigsäure in German).
Finally, you may have wondered why I called this "atavisms" of acetic acid in the first place. Well, an atavism is some genetic information that is no longer expressed in further evolved species, but is still inherited from earlier ones in the genetic code. I thought this is a good metaphor for the topic presented here, plus it alliterates nicely with the rest of the title, don't you think?
PS: I just remember another good example of how words from diverged languages can be a sense of humour. I have been to the Netherlands once, which is inhabited by a serious cycling nation. Of course this results in a vast number of traffic signs referring to the bikes. The funny thing is the Dutch word for bicycle: "fietsen". A Dutch bike is a "footie", because you use your feet to make it move. But it gets even better than that: a motorized bike is a "bromfietsen", "brom" being just an onomatopoetic (i.e., "soundpainting") reference to the noise of the engine. This casual description is very delightful ("cute") to my German ears. - I count on the understanding of all potential Dutch readers and/or their affiliates. Maybe they would like to contribute as well in the comments section?

John Hancock Center

I took too many photos on my two trips to the skydeck of the John Hancock Center ("it would be the nicest bird view of the city - if only the birds could fly that high") to publish them here. Instead I did the 360° tour with my camera. That should give you an even better impression of the scene. I hope you like it. I certainly do!
As I said above, I did two trips to the Hancock. There is the option of buying a Sun and Stars ticket, which grants two admissions within 48 hours. Thus you can experience the view at two different light conditions. And that was only slightly more expensive than the single ticket, so that was my best choice. I did the daytime trip on Saturday afternoon, and I came back for the nighttime view on Sunday night. I should have maybe come back already on Saturday night, as I missed Superbowl XLIII - but I had to charge the battery of my camera, along with that of my body. I do hope that I will get another chance to watch a Superbowl game while being in the U.S., though. I also couldn't resist buying a whole lot of touristy memorabilia, including a Chicago Bears cap. At least I'll have my gear when the next Superbowl comes up.
... It just occurred to me: referring to the name of this blog, you might say, "the owl missed the bowl". (See the very first entry for an explanation why I called this blog The Owl's Nest.)

More Music

After a successful time in the lab, we experienced what everyone in the UHV community goes through occasionally: a downtime. Right before the last series of experiments that ought to complete the data for the upcoming publication, a tiny cable came loose in the ultra-high vacuum (UHV) chamber. For the non-scientists among the readers of this blog, I shall explain UHV quickly. I study surfaces, with respect to their chemical performances (i.e., reactivities). This kind of experiments requires the use of the so-called ultra-high vacuum or UHV, which means a pressure level at the equivalent of outer space. Essentially the chamber is empty, and as a consequence, the gas phase contained in it is negligible. Hence, the surface in question will adsorb contaminations only very slowly. As you can imagine, obtaining such an environment is technically demanding. Other than good pumping, a procedure called bake-out is required, in order to remove moisture from the air that gt into the chamber, when it was opened the last time. - Therefore the loose wire is quite annoying, because it means a downtime from the experiments for several days, until the repairment is carried out and the vacuum is fully restored. Unfortunately the screw that was supposed to hold and connect the wire got stuck in its hole, and I was unable to move it at all. Eventually I even broke its head off, which means the mechanical workshop will have to remove the remainder and make a new screw for me. Estimated downtime: one week.
Back home in Berlin, this would have affected my mood quite a bit. But since I do not have to pass an exam at the end anymore, I see it a lot more relaxed. In fact, I decided to use the free time on Saturday to finally do some sightseeing, which I have been neglecting in the past. From one of the earliest posts in this blog, you might remember that you can see the Sears Tower (the tallest building in North America) quite well from the L station close to my work. It has been luring me into a visit ever since my arrival - but since I also needed to do some shopping, I decided to give the John Hancock Center a visit.
Named after a highly successful businessman, it is the fourth-tallest building in Chicago, after the Sears Tower, the Trump International Hotel & Tower (topped out in 2008 and currently being finalized), and the Aon Center (in descending order). For the sake of completeness, it be mentioned that the Chicago Spire is planned to be the new second-tallest building in town ina few years from now, but the current financial crisis has stalled further work for now, and it might even kill the project altogether.
Anyways, I did pay "Big John" a visit, and while making a connection from the blue to the red line at Jackson on the way there, I could enjoy some more music. Check it out - and make sure you don't miss the crazy guy in the audience!