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Project Idea? [sadface]

  1. Apr 19, 2008 #1
    I have a chemistry posterboard project coming up, and, to not waste time and actually learn something, I want it to be something related to quantum physics. Does anyone have any idea what it could be about so that it still has some 10th grade chemistry in it? Or no chance? D=
  2. jcsd
  3. Apr 21, 2008 #2
    anyone? =(
  4. Apr 21, 2008 #3
    Thank you for the bump. I didn't notice this question earlier.

    Well, how much quantum mechanics do you already know?
    Do you know about the hydrogen energy levels and wavefunctions? (and what chemists call the s,p,d,f,etc. orbitals?)

    If so, discussing the binding energy and wavefunctions of a hydrogen molecule (so you can use the binding and anti-bonding diatomic orbital picture that may have been presented in your high school chemistry). Also interesting would be to look at methane (in chemistry terms, sp3 hybridization of the orbitals). If you want to see a series of the different hybridization of orbitals, maybe: ethane (which is sp3 on each carbon), ethylene (sp2), acetylene (sp).

    For pretty "poster pictures", I'm sure you can find stuff on the internet discussing this with pictures.

    EDIT: A cursory search shows wikipedia has some nice public domain images you can use, as well as some articles to get you started (of course remember the usual caveat - always use books and more reputable sources once you know what you need to look for... wikipedia should not be a final destination nor treated as a primary source).

    EDIT(2): If this isn't in depth enough (say for instance this all has already been covered in class), I can give suggestions to make it more advanced (more heavily quantum mechanics based) if necessary.

    EDIT(3): I'd be willing to give plenty of extra help if you could get a teacher to answer my question :) https://www.physicsforums.com/showthread.php?t=229904
    Last edited: Apr 21, 2008
  5. Apr 23, 2008 #4
    As I mentioned, I can easily suggest more advanced ideas if you want.
    The first thing to realize is that the s-p-d-f orbitals and hybridization is a good starting point, but is far from the whole picture.

    While the hydrogen atom has an exact solution (well, non-relativistically and ignoring magnetic effects), no multi-electron atom or molecule has an exact analytic solution (not even simple old helium). When someone wants to compare experiment to numeric theoretical predictions, we need to come up with some way to use quantum mechanics to get numeric answers.

    Even simple methane is interesting. What are the vibrational modes and their energies? And which ones are FTIR active (an experimental measurement chemists often use)? A lot of interesting quantum mechanics (and group theory if you want to get into that) is involved in these questions. Also, there are the questions of excited states of the molecule... what are their energies, which can absorb (this question also can involve group theory if you wish), are they stable states or does the molecule break up?

    It turns out that methane has an excited singlet state, but not a triplet state. Something that just rough s-p-d-f arguments probably can't show... more detailed quantum discussions are needed.

    This field is sometimes called "quantum chemistry".

    While the physics, math, and concepts are somewhat more complicated, there are free programs out there designed by people working in the field to do such calculations. They use them with a lot of computer time to make some state of the art calculations, but you can use it to do simple calculations quickly on your PC and learn about the concepts (and get some nice graphs and such) without having to get into the messy calculations yourself.

    If you're interested, just let me know.
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