Chemistry Grad Student taking Graduate Level Physics Courses

[HeavyMetal]

Hello all,

I am a first year graduate student in chemistry studying electronic structure theory. I am fascinated with physics, and a lot of what we work on deals with some heavy QM and mathematical methods. I've asked my advisor and he supports my choice to take some courses in the physics department. I have signed up for a graduate level quantum mechanics course and a senior level [undergraduate] solid state physics course. These should be excellent courses for my work, and contingent upon my success in these courses, I will take the second semester of quantum mechanics and the graduate level analogue of solid state -- a quantum theory course. I am very excited for this semester to start!

Here's the catch: I haven't taken any courses in graduate school yet -- chemistry or physics -- and I'm finding myself a bit nervous...these nerves have the potential to hamper my ability to focus and learn effectively. I won't say that I doubt my abilities because I'm pretty good at adapting, but this could be a very quick change for me. I can adapt, but I'm just not quite sure about how rapidly.

1.) Can I expect the professor to supply at least some of the minimal background information?
2.) Generally, what should I expect?
3.) Would anyone like to offer some wise words of advice? Admonition? Commiseration? COMFORT?

Thanks,
HM

 

[Dr. Courtney]

If you had two strong semesters of undergrad PChem you might be OK, as there is a lot of overlap with undergrad Quantum Mechanics. On the other hand, I majored in physics, had two semesters of undergrad QM, and I still decided to re-take undergrad QM before attempting grad QM out of Sakuri. (As taught by Goldstone at MIT).

 

[HeavyMetal]

If you had two strong semesters of undergrad PChem you might be OK, as there is a lot of overlap with undergrad Quantum Mechanics. On the other hand, I majored in physics, had two semesters of undergrad QM, and I still decided to re-take undergrad QM before attempting grad QM out of Sakuri. (As taught by Goldstone at MIT).

I scored at the 95th percentile on the ACS standardized exam, which wouldn't tell the full story, but at least attests to my strong familiarity with physics from the chemistry standpoint. My worry is that we did not do anything with the more rigorous treatments (e.g. Hilbert space methods, bra-ket notation, operator theory, etc...). I have learned a decent amount on my own and am highly self-motivated.

My math background: integral/differential calculus, differential equations, vector calc, and linear algebra. Some self study in the more in-depth aspects of these courses.

 

[radium]

Ok so I assume you are in some sort of theoretical quantum chemistry if you are interested in electronic structures of materials. Are you familiar with DFT?
I actually worked in quantum chemistry as an undergrad physics major (on the far physics side) and knew a lot of people from my group who did things similar to what you want to do in regards to classes. I think the most important thing for you to think about is your math preparation as I think often the chemistry major does not require as much math. You should be very comfortable with multivariable/vector calculus, ODEs/PDEs, Fourier analysis, linear algebra. Complex analysis also really helps. For Sakurai it also really helps to have some knowledge of group theory. I think you may learn some representation theory in inorganic chemistry which is exactly what I mean (along with Lie groups).

I assume you did things like solve the schrodinger equation for the hydrogen atom in pchem.

And on a final note, I actually read a good amount of griffiths and Sakurai during the summer and actually skipped undergrad quantum (I had taken the math I listed and had taken a class in group theory and topology, and other sophomore/junior level physics courses). I was completely fine and ended up doing very well in the class. It also helped my research tremendously.

 

[HeavyMetal]

Ok so I assume you are in some sort of theoretical quantum chemistry if you are interested in electronic structures of materials. Are you familiar with DFT?

Yes, and yes :). We work with both wavefunction methods and DFT.

I actually worked in quantum chemistry as an undergrad physics major (on the far physics side) and knew a lot of people from my group who did things similar to what you want to do in regards to classes.

This is very comforting to hear! Yes, the stuff we will be doing is definitely more on the condensed matter physics side of things. Some treatments should include second quantization and other CMT methods.

I think the most important thing for you to think about is your math preparation as I think often the chemistry major does not require as much math. You should be very comfortable with multivariable/vector calculus, ODEs/PDEs, Fourier analysis, linear algebra. Complex analysis also really helps. For Sakurai it also really helps to have some knowledge of group theory. I think you may learn some representation theory in inorganic chemistry which is exactly what I mean (along with Lie groups).

I assume you did things like solve the schrodinger equation for the hydrogen atom in pchem.

If this is the extent of the math background, and I can pick some stuff up along the way, I should be set. I don't need to be a diff eq guru, do I? I expect that after I leave the course, I will be. I'm just a bit rusty.

And on a final note, I actually read a good amount of griffiths and Sakurai during the summer and actually skipped undergrad quantum (I had taken the math I listed and had taken a class in group theory and topology, and other sophomore/junior level physics courses). I was completely fine and ended up doing very well in the class. It also helped my research tremendously.

These are all great things to hear! I am much more confident now. I read through parts of Griffiths' 2nd edition this summer, as well as various parts of other texts including one that gave a good account of [anti]commutators, Dirac notation, and linear algebra.

Anyone have anything else to add?

Thanks,
HM

 

[mpresic]

When I was an undergraduate, we used Merzbacher as a text for Junior/Senior level QM. The chemistry students also used Merzbacher for their graduate course. When I brought this up to my QM professor, he said, (in defense of the chemistry grads) there are parts of Merzbacher that we won't touch (at least for the first semester). In general, I think QM from Merzbacher, or Messiah, or traditional QM texts would be OK. However, these days graduate QM is usually taught out of Sakurai, Sakurai believes in the "shock" treatment to introduce spin systems early. This does not dovetail as nicely into the chemistry curriculum you may be most comfortable with. Griffith begins gently, which may be misleading. Griffith does not begin with spin systems and state evolution.

I am not sure you can rely on your professor giving you background material. He will probably gear his course to the 20 or so graduate physics students than the one or two chemistry students. If you a lucky the QM will start with a historical development or start with the Schroedinger Equation and not the most esoteric non-intuitive concepts right out of the box.

I expect you can do well, but it would be fortunate if you could leverage with your P-Chem knowledge (Hydrogen Atom; quantum numbers; molecular spectra; some spin) knowledge right from the beginning rather than be put through the shock treatment of Sakurai.

As an aside., Years ago, I could not take quantum until the second semester junior year in my physics program. Because I was impatient, I deliberately took P-chem from the chemistry department to hit (about 2/3 semester of) QM in my 1st semester of my junior year (a semester earlier). I noticed many physics students in the physics forums who are impatient to be introduced to QM have not caught on to this trick.

 

[TeethWhitener]

I took grad level QM in the physics department when I was a chem grad student (first semester of my first year). This was after having taken 2 semesters of grad level QM in the chemistry department as an undergrad. The physics QM was significantly harder, at least for me. I passed, but not with flying colors. However, it was a good experience in the sense that I learned a lot more than I would have had I stuck to the required chem QM (most of which I had seen during undergrad). I have friends in chemistry who took grad level mechanics and stat mech from the physics department, and they attest that (at least for stat mech) it was quite a bit harder than the courses offered in the chem department.

Part of the difficulty is that physics has a different focus than chemistry. Physics QM is more about introducing a general theory that can be adapted to many different areas of physics and can be built upon as a preparation for later QED or QFT courses. Chemistry QM is more about looking at applications to molecular physics, electronic structure theory, and spectroscopy. QM in chemistry is really a tool borrowed from physics, just as, e.g., linear algebra in physics is a tool borrowed from math.

It's worthwhile, but if I had to do it over again, I might not jump into it right away my first semester in grad school.

 

[HeavyMetal]

So I ended up doing the opposite: I ended up taking an undergrad solid state physics course, which has very little QM! This has been nice so far, and I seem to be grasping the material even better than most of the physics majors. We've learned about the Drude model and we've solved the electromagnetic wave equation for coupling to a surface plasmon. Very neat stuff, and I've been wanting to work with Maxwell's equations for quite a while. I'm very excited to take the graduate level quantum theory course for solids next year.

As for QM: I'm taking a quantum chemistry course that is being taught by a physicist, and he is well versed with this material; it's his field of research. It is decently in depth so far, and we've been following Szabo and Ostlund for it's account of linear algebra. We're also getting started on Levine for a different perspective and some applications. It's an excellent course so far, and I think I made a good choice for coursework.

 

[mpresic]

Glad to hear you are doing so well. I remember when I started taking a course in graduate solid state physics, I noticed it was quite similar to chemistry as well. Quantum chemistry sounds like a good choice as well.