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Thread: NMR and Microwaves

  1. #1
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    Default NMR and Microwaves

    The development of dye lasers has not progressed much in the last couple of decades. There are some prospects for new borane based dyes, but the significant impact of triplet absorption prevents all these lasers from dominating visible wavelength sources. Oxygen and COT are among the compounds that speed triplet quenching, but they are at best, modestly effective.

    I was thinking about NMR and the interaction of high frequency radio waves and hydrogen and carbon. These nuclei possess spin and can be identified based on the local electrical environment and its effect on their resonance frequencies. If they can be influenced then maybe the local electrical environment can be influenced in turn by a radio frequency input and/or a strong magnetic field.

    A microwave oven heats water, but not hydrocarbons like plastic. The molecular bonds in water are stretched and compressed when they absorb microwaves of the correct frequency.

    Could a scanning, broad-band microwave transmitter be tuned so as to interact with excited dye molecules and preferentially stimulate the relaxation of the triplet state to the ground state?

    I have no idea if this is a reasonable question. Is there any existing research where radio waves are being used to modify chemical states or reactions?

  2. #2
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    Lightbulb

    Quote Originally Posted by planters View Post
    ...Is there any existing research where radio waves are being used to modify chemical states or reactions?
    I heard they're trying to use HAARP to fix the maniacal highways-in, and/or just plain melt New Jersey?

    Seriously, if anyone knows, this guy will.. http://www.tunablelasers.com/fjduarte.htm ..I used to do many of his 'pub drawings' (table / optical experiment layout schems) at Kodak.. Spent WAY too-much time at his lab, asking a bajillion questions.. Learned a LOT about dye lasers / gratings from him, tho.. Very cool stuff..

    fwiw..
    j
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

  3. #3
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    Default

    When I was in grad school, a lab in my building was doing some interesting work with microwave-catalyzed biofuel synthesis.

    Not sure how directly applicable these papers citing similar research are to your specific quest, but hopefully they'll be of some use:
    http://www.jocet.org/papers/019-I021.pdf
    http://pubs.acs.org/doi/abs/10.1021/ar400309b

  4. #4
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    These are both good posts. I know about Duarte. I have some of his books and you are right he will probably know if anyone alive knows. I also see that he has an educational bent. He is probably used to some pretty naive questions from undergrads. My idea is pretty radical and is either very naive or it might be interesting to him. Who know, he may have tried it...has the "T" shirt... I'll email him.

    The suggestion, in the second paper, that high frequency radio waves may actually effect these chemical reactions directly, as opposed to the sledgehammer of simple heating is encouraging.

    Here is another interesting overview that suggests that there may be something to this. Note the kinetic control section and the caveat that the intermediate must have a reasonable lifetime. The triplet state survives for many nsec and even usec.

    http://cem.com/page130.html
    Last edited by planters; 06-11-2015 at 06:36.

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