Friday, August 30, 2013
Is caffeine a PED? In the Information Age, mental performance is critical to many job functions. For scientists, it could mean the difference between making a grant deadline or not, solving a structure, or submitting a paper before your competitors do. So what's wrong with drinking a little extra coffee on a given day in order to be a little sharper? Indeed, many people drink coffee routinely every day, and it's rarely banned. (The exception to prove the rule being the dictum from the Latter-Day Saints that drinking hot drinks, such as coffee, is unhealthy.) You could argue that intent is a determining factor in the sense that it's a PED if you consume it too enhance performance, as in for example to stay awake later or to wake up in the morning?! But isn't that just the way that most people consume caffeine? I drink three double espresso's/day. That's approximately 350mg of caffeine and fortunately well below my LD50 of approximately 15 grams. It's legal, it's likely a PED, but I'm not giving it up!
Tuesday, August 27, 2013
NDEW2013, I described the now oft told refrain about the overburdening of female and URM* faculty. In fact, this affects anyone in a department who is different in some way that adds to the faculty's strength. For example, in Georgia Tech's chemistry department, Mostafa El-Sayed is presently the only member of the National Academy of Sciences. So everyone wants him to be on their committee. But even he cannot be on every committee. Similarly, a female or URM faculty member is invariably asked to be on far too many committees. Let's call this the diversity tax as it adds an extra layer of work to such faculty. The existence of the diversity tax is not without good intentions. After all, everyone wants university and professional committees to be diverse. The trouble is that there are necessarily too few such faculty and hence they are asked to participate much more often than their colleagues. Moreover, only a few of those committees are actually useful to them at a given stage of their career.
Meanwhile the diversity tax goes further because female and URM faculty are invariably taxed in several other service roles. There's no doubt that said faculty are willing and interested to help. The trouble is that it's difficult to say no (for a number of reasons) and even the mental tax of doing so is part of the problem. Good intentions to limit the requests often fall on individuals not being invited to the tasks that are most in demand (because it's easy to fill those slots, and it apparently avoids further taxing female and URM faculty.) Thus the solution for the diversity side is too tricky to solve on the demand side. Instead, I advocate for correcting it on the supply side. Namely, if you see a faculty member being limited by the diversity tax, then give them more support—e.g., administrative assistants, teaching relief, research scientists, etc. This will put them on an equal playing field with their colleagues, and will help your department in the long run.
*URM stands for under-represented minority
Friday, August 23, 2013
A similar question arises when you run a research group. Each of my students requires just the right balance of training and freedom to venture into our joint research problems. She or he has little choice—once in the group—but to trust in my approach and in our group culture. That is, unless there is a catastrophic event that results in them leaving before achieving their degree. Like the little boy in the song, though, once graduated my students have the choice to remember their experience positively or negatively. If the former, this gives rise to an alumni network of students who continue to interact with each other and me. Thus the seeds of collaboration and interaction planted during their training continues to give back substantially to the other members of my group and me. But it's my choice to make those investments, and sadly not everyone makes this choice. So one of the pieces of advice to the students at the Future Faculty Workshop was simply: invest your time in mentoring the kind of group you want now and later. The former is your choice, but you will reap the latter accordingly.
*The lyrics of Cat's in the Cradle were written by Sandy & Harry Chapin, though I have mostly heard them on the Cats Steven soundtrack.
Friday, August 16, 2013
What was my advice?
- First and foremost, students should recognize the power of the network of their peers. Both as students and alumni, they will have a common bond through their time at Tech. While in college, they can certainly help each other learn faster and more efficiently through study groups. After graduation, they can help each other accelerate their careers through continued collaboration.
- The single most important thing they can do to succeed is to GO TO CLASS. Most college lectures do not include an attendance component. However, student performance tends to correlate well with attendance.
- Students should interact with faculty, tutors, teaching assistants and other instructors as much as they can. We all post office hours, so go to them, don't be shy and ask for help on whatever you don't understand. If you wish to meet your instructor beyond posted office hours, then pay attention to whichever mode she or he suggests you use. Some instructors will be happy to receive texts on the classroom bulletin board system, others will prefer drop-in visits at their office and others will prefer e-mail, but few will prefer all of these.
- As you ponder the choice of your major, remember that this decision is primarily going to affect your time in college and your first job or post-graduate program. After that, through the typical 3-4 career changes that most people undergo, you will likely be working in jobs very different from your major. So DON'T PANIC. You need only figure out what you will enjoy doing for the next 4-5 years. You might as well choose something that you like doing, and that you can do well.
- Finally, my parting bits of advice were: "Be prepared, be engaged, stay the course, challenge your intellect, try new things, have fun, ... don't die."
Of course, these are simply a summary of the main points that I made. My actual presentation involved the type of discourse (with an audience in the several hundreds) that I learned from my use of active learning modalities. I had them raise their hands, talk to each other, repeat after me, and even laugh (sometimes). If nothing else, they might remember that they can listen to a group of professors for nearly an hour without falling asleep.
Wednesday, August 14, 2013
The road between chemistry and physics has two lanes. One of these heads from chemistry to physics. Call it physical chemistry. The other lane heads from physics to chemistry. Call it chemical physics. But the road is the same road. As such, there truly is little difference between the names. However, there is a subtle difference due to the fact that each is pointing in a different direction. Chemistry has historically been an empirical science over which principles are constructed. Physics has historically been driven by axiomatic principles that give rise to the nature that we see. In likewise fashion, the Journal of Physical Chemistry has always tended to publish a slightly greater portion of phenomenonolgical results, that in turn have practical implications in advancing the field. Meanwhile the Journal of Chemical Physics tends to publish a slightly greater proportion of theoretical results and precise measurements, that in turn have implications on advancing fundamental principles. But both are moving towards the middle. As such, even these subtle differences should soon be lost (if they haven't already).
A different journal run by the Royal Society of Chemistry replaced the Faraday Transactions and formalized the blurring between the two names by simply naming itself as Physical Chemistry Chemical Physics (PCCP) in 1999. There is evidently plenty of room for us to publish our work. More importantly, the true meaning of physical chemistry and chemical physics is fundamentally the same and truly lies on a one-lane road between chemistry and physics.
(This is the sixth and last post in a series starting with the first one on interdisciplinary sciences.
Click here for the previous post.)
Monday, August 12, 2013
It's no surprise that chemists care about chemical reactions. We want to know both how the reactions take place—mechanism or pathway—and how much time it takes to happen—rates. One of the most successful, though approximate, theories has been transition state theory (TST), in part, because it provides an answer to both questions. You simply need to find the saddle (or col) on the potential energy landscape between reactants and products. That bottleneck, which can be described with varying levels of fanciness, gives you a sense of how the atoms in the reacting system have to distort so as to proceed to products. The energy of the bottleneck can be used in a well-known formula to obtain the rate. Recently, however, Joel Bowman and others have discovered the possibility that the reactants could avoid the bottleneck entirely. These roaming trajectories thus pose a challenge to TST, and have generated a lot of well-deserved buzz.
In those cases when roaming trajectories wander so far away from the transition state (bottleneck) that new product channels (such as radical molecules) become accessible, there is no doubt that everything goes topsy turvy. However, we were curious as to whether roaming trajectories would turn TST upside down even when such channels are not available. In recent work, we studied the ketene isomerization reaction—that is when it interconverts from one form to another—and found that it gave rise to roaming trajectories (such as the one pictured here.) Unfortunately, TST remains reasonable for this system as long as one is careful to generalize the dividing surface associated with the bottleneck so as to appropriately include roaming trajectories. So perhaps all remains good with TST after all?!
The title of the article is "Effects of Roaming Trajectories on the Transition State Theory Rates of a Reduced-Dimensional Model of Ketene Isomerization" and the work was funded by the AFOSR. It was released recently at J. Phys. Chem. A, ASAP (2013). (doi:10.1021/jp402322h)
Click on http://dx.doi.org/10.1021/jp402322h to access the article.
So in the mid twentieth century, we had a subtle distinction between physical chemistry and chemical physics. It was made concrete according to which of the two American journals you chose to publish your work. Physical chemists who wanted to go beyond the confines of thermodynamics had to turn to the physics community. The amount of chemistry that physical chemists needed to learn and teach made it difficult for them to fulfill the complete physics undergraduate curriculum or pursue doctoral degrees in physics. So where was a physical chemist/chemical physicist to teach? In practice, the answer was chemistry departments in the States, but often physics departments in Europe or other parts of the world. This gave root to yet another distinction between the names. To put it simply, you did physical chemistry in chemistry departments and chemical physics in physics departments. (Students went to both.) Of course, the distinction was in name only because most of the practitioners could easily transfer their appointments between the respective departments. Indeed, several of the editors of the Journal of Chemical Physics have held appointments in chemistry departments. The irony here is that physical chemistry become a core component of chemistry curricula when the subject is interpreted to have the scope of chemical physics.
(This is the fifth post in a series starting with the first one on interdisciplinary sciences.
Click here for the previous post.)
Saturday, August 10, 2013
The power of thermodynamics to describe chemical processes—like reactions and phase transitions—is so great that it still fills much of the material that we teach in general chemistry courses. It's useful to understand that atoms and molecules exist as indivisible objects—up to chemical bonds—which allows us to create balanced reactions that also reflect energy transactions. So what need does a chemist have for any other physics? Sadly, the American Chemical Society (ACS) Journal of Physical Chemistry (founded in 1896) and their editor—Wilder Bancroft—answered this question in the negative well beyond the 1920's. Lest you think that Bancroft was a heretic, it is important to note that he was a graduate student of Ostwald and a postdoc of van't Hoff! Under Bancroft's rule, the Journal defined physical chemistry as only that science which involved the use of thermodynamics to understand chemistry. Pretty powerful, yes, but also limited.
(This is the fourth post in a series starting with the first one on interdisciplinary sciences.
Click here for the previous post.)
Thursday, August 8, 2013
http://academictree.org that track these lineages. An early such project started at Illinois catalogs the academic genealogies of their faculty (http://www.scs.illinois.edu/~mainzv/Web_Genealogy/) and a few other notable chemistry departments. An interesting book by Paul Servos tracked the history of physical chemistry according to the line of chemists starting with Friedrich Ostwald through to Linus Pauling...
Linus Pauling (1901-1994)
Cal Tech, 1925
NOBEL PRIZE (CHEM), 1954
NOBEL PRIZE (PEACE), 1962
Roscoe Gilvey Dickinson (1894-1945)
Cal Tech, 1920
Arthur Amos Noyes (1866-1936)
Friedrich Wilhelm Ostwald (1853-1932)
Dorpat (Latvia), 1878
NOBEL PRIZE (CHEM), 1909
The funny thing is that the academic genealogy of most (American) physical chemists overlap with at least one of these nodes (either through the graduate student or postdoc lines). Mine is no exception as you can see from my academic genealogy (at http://www.chemistry.gatech.edu/rig/cgen.html) which meets the lineage at Pauling. One notable exception is Ira Remsen who was among the first of the American Professors to train and sponsor Ph.D.s in this country (at the Johns Hopkins University). I don't know the extent to which the academic genealogies of physical chemists around the world also trace back to Ostwald. I would be happy to hear if yours does or does not!
The point of all of this is that physical chemistry as a field has been critically shaped by the intellectual movements from Ostwald's school. It's not an exclusive club, however, nor should it prevent such physical chemists from expanding beyond. Indeed, what has made physical chemistry an exciting field is the ever changing paradigm shifts that have advanced our fundamental understanding of the chemistry and physics of atoms and molecules. This requires diversity of thought. It has evidently come from the subsequent generations despite our tight academic lineages.
(This is the third post in a series starting with the first one on interdisciplinary sciences.
Click here for the previous post.)
Tuesday, August 6, 2013
The interdisciplinary field lying between chemistry and physics took hold in the late 19th century. Ostwald recognized the power of the new physics of the day—thermodynamics—to help make sense of the energetics or molecular motions and reactions. Thus was born the field of physical chemistry, and the eponymous journal within the American Chemical Society. The trouble is that when new physics—such as quantum mechanics—came along, the editor of the Journal of Physical Chemistry at the time wasn't ready to accept it. This led to the rather odd definition of physical chemistry as being limited to the thermodynamics of chemical processes. This, in turn, necessitated the definition of a new interdisciplinary field, chemical physics, which included the use of all physics (even thermodynamics) to understand chemical processes. As the corresponding eponymous journal was subsumed under the umbrella of the American Institute of Physics, some chemists (though not most) did not make the jump to chemical physics. This, in turn, led the Journal of Physical Chemistry to focus on topics in the middle of the 20th century with decreasing relevance. (Fortunately this misdirection did not persist, and the happy ending is coming soon!) Meanwhile, the name confusion continues to recur as students routinely ask me what exactly is the difference between chemical physics and physical chemistry today. My answer to the question follows in the posts to come!
(Note that this is the second post in a series. Click here for the previous post.)
Sunday, August 4, 2013
In the (post)modern science at the turn of the 21st century, the fundamental problems confronting us appear to require a new breed of scientist: interdisciplinary scientists who act as connectors between distant fields. Examples include so-called energy scientists, environmental scientists and data scientists. It has also driven the construction of institutes or buildings, such as the Molecular Sciences and Engineering Building where I work at Georgia Tech, that collocates students and practitioners in order to advance interdisciplinary research. The story of the development of physical chemistry coined around 1752 by Mikhail Lomonosov and taking root in the late 19th century doesn't diminish the value of these recent interdisciplinary threads in science. Rather, it is but one of the many examples in which the development of ties between existing disciplines—chemistry and physics in the case of physical chemistry—has led to major advances in the sciences. Thus interdisciplinary sciences are not a modern fad. History tells us that their growth has been a critical part of the practice of advancing science all along. In a short series of posts, I plan to summarize how the development of this emergent field had dramatic impacts on the practice of its science.