Sciencemadness Discussion Board

magnetic field's effect on triplet state transitions

ThatchemistKid - 22-10-2010 at 19:48

Today in class (Quantum Mechanics) we were discussing singlet and triplet state transitions in multi-electron atoms.

I asked the instructor a question. The question was is there a way to influence the way an atom excites, say to induce to go into a triplet state? He said that magnetic fields can alter the selection rules and can influence the transitions. When I asked him why that was and what was going on, he said we are not even going to go there...

I attempted to look up information on google and all the information is in the form of patents that i cannot access or plainly goes over my head.

Could anyone shed some light on what is going on?

Thanks in advance.

[Edited on 23-10-2010 by ThatchemistKid]

Nicodem - 23-10-2010 at 00:28

You can not obtain scientific data in patents. Patents are state documents that grant a monopoly on the production and commerce of a certain consumer product. They are law related documents and not scientific documents - though they must disclose information on the manufacture of chemicals if they are patents on chemical production and commerce. Also, it is unusual that you say you can not access patents. These must be accessible and made public due to patent law and regulation, and most countries already digitalized them. You can use patent office internet sites to access them and download as PDF (for example, using ep.espacenet.com). You can even access patent applications 18 months after of their filing, even those that were never granted to become patents.

Try searching scientific articles instead. Or at least check some encyclopaedias or school books if you want a more pedagogic explanation and you are not interested in details. Search for the magnetic field induced energy level degeneracy of particles possessing a magnetic spin: Paschen-Back effect and Zeeman effect.

DJF90 - 23-10-2010 at 01:03

You want to learn Quantum mechanics? Try this book, its great: Quantum Chemistry, Donald McQuarrie, 2nd edition. Unfortunately I've had only enough time to read the first few chapters, and flick through some other pages as I've needed them.

DDTea - 23-10-2010 at 04:01

You may want to look into how electron paramagnetic resonance works.

Quantum mechanics is something I am constantly trying to learn and understand. It's exciting but challenging, but also worthwhile. One thing I have learned, though, is not to ask why something works the way it does in QM. Trust the math :P

"You cannot hope to understand quantum mechanics, you can only get used to it."

merrlin - 23-10-2010 at 11:59

Quote: Originally posted by ThatchemistKid  
Today in class (Quantum Mechanics) we were discussing singlet and triplet state transitions in multi-electron atoms.

I asked the instructor a question. The question was is there a way to influence the way an atom excites, say to induce to go into a triplet state? He said that magnetic fields can alter the selection rules and can influence the transitions. When I asked him why that was and what was going on, he said we are not even going to go there...

I attempted to look up information on google and all the information is in the form of patents that i cannot access or plainly goes over my head.

Could anyone shed some light on what is going on?

Thanks in advance.




[Edited on 23-10-2010 by ThatchemistKid]


The best textbooks that I am aware of are:

Introduction to Dynamic Spin Chemistry
Magnetic Field Effects on Chemical and Biochemical Reactions
Hisaharu Hayashi

Chemical Generation and Reception of Radio- and Microwaves
Anatoly L. Buchachenko and Eugene L. Frankevich

Magnetic Isotope Effect in Chemistry and Biochemistry
Anatoly Buchachenko

I have previously posted a number of articles in the following threads:

http://www.sciencemadness.org/talk/viewthread.php?tid=12028

http://www.sciencemadness.org/talk/viewthread.php?tid=12024#...

Of the articles posted, I would recommend the following as a point of introduction:

Magnetic Isotope Effect-Nuclear Spin Control of Chemical Reactions
A Study of Spin Chemistry
Turro_spin_lectures
Control of a Chemical Reaction by Spin Manipulation of the Transient Radical Pair


My own interest is in the spin modification of electrolytic reactions, and a pertinent paper is attached below. I corresponded with the author and he was surprised to learn that the magnetic isotope effect had been demonstrated in heavy elements subsequent to his work. I have corresponded and/or spoken with Buchachenko, Turro, and others in the field of spin chemistry and the consensus is that the existing theoretical framework is not extensive enough to dismiss to possibility of spin modification of electrolytic reactions, and that experimentation is required. The biggest obstacles appear to be spin-orbit coupling and the exchange interaction. My own belief is that microwave pumping of spin states of species resident in the double-layer region of a cathode can be done with an intensity and efficiency that cannot be achieved through conventional radiation/waveguide technology, and that a spin-polarized current can be obtained from a cathode in an electrolytic cell. My posts on this subject seem to attract flames, so feel free to send me a U2U message.

Attachment: Spin_dependent_electrochemical_kinetics_at_a_semiconducting_photocathode.pdf (1014kB)
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