Saturday, January 13, 2018

CHEM 418 Nuclear Chemistry, Winter 2018: Lecture 4 Alpha Decay

This lecture discusses alpha decay in radionuclides.  Theories on alpha decay are presented. Systematics and energetics involved in alpha decay are presented.  The correlation between Q value and decay energy is described.  The Geiger Nuttall relationship is provided, described, and utilized in a model for alpha decay. Tunneling is also exploited to described alpha decay, coupling energy and half-life.  Gamow calculations are shown to reflect the Geiger Nuttall relationship. Hindered alpha decay is discussed. Hindered alpha decay is employed to described nuclear properties. Hinderance factors are described, along with how they are calculated and where they can be found. Proton and other charged particle emission are presented. The lecture time is 50 minutes.  The lecture is assigned on Saturday 13 January 2018 and due Thursday 18 January 2018.  The answers to PDF quiz 4 will be posted Friday 19 February. 

31 comments:

  1. Lecture reviewed and quiz emailed.
    Was there only 1 mistake in question 3?
    And for the 2nd question I wasn't quite sure what else I was suppose to mention or talk about.

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    1. thanks for the comment. There was only 1 mistake in Question 3. In question 2 the number of neutrons and number of protons has an impact. You can review the lecture notes, page 15 on hindered alpha decay is a good place to review.

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  2. I have viewed Lecture 4 however I don't quite understand question 3 on the quiz.

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    1. There is an error in the figure from the table of the isotopes. Something in the question is incorrect. You can review the notes on heavy ion decay. You should take not which isotope is often the daughter from heavy ion decay.

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  3. Lecture viewed and quiz sent.

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  4. viewed lecture 4 and submitted PDF quiz 4.

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  5. Viewed lecture 4 and emailed quiz 4.

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  6. Lecture viewed and quiz done. - Ryan Cheung

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  7. Many thanks for the comments and PDF quiz.

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  8. If you have a question on question 3 of the PDF quiz for alpha decay please read some of the comments posted in the blog.

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  9. Lecture has been viewed, and quiz was submitted via email.

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  10. Lecture has been watched, and the quiz was submitted in canvas

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  11. I reviewed the lecture and submitted the quiz on canvas. Thank you!

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  12. Lecture done, PDF quiz sent.

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  13. I have reviewed lecture 4 and emailed you quiz 4.

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  14. At 37:30, the proton dripline is described as proton rich, however on that graph the neutron dripline is more proton rich. Why then would we focus on the proton dripline instead of the nuetron dripline?

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    1. I think there is an error or something misspoken, could I get more clarification? Thank you for your time and consideration.

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    2. Many thanks for the question. A nucleus being proton rich is relative. For any given isotope, a lower A means a higher relative percentage of protons.

      The nuclei that decay by proton emission have a larger relative abundance of protons. This relative proton excess means that emission of a proton can result in a more stable nucleus.

      Consider the isotope 16Ne, which decays by double proton decay. Neon has 10 protons, so the nucleus is composed of 62.5 % protons. The 2p decay results in 14O, which is 57.1 % protons. This nucleus is less proton rich than 16Ne. The isotope 14O is a positron emitting nucleus, so it stable with respect to proton decay.
      The isotope 20Ne is stable and has a nucleus with 50 % protons.

      Please let me know if you have any further questions.

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  15. I have reviewed lecture 4 and emailed the pdf quiz.

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  16. Reviewed lecture 4 and submitted quiz.

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  17. I reviewed Lecture 4 and submitted PDF Quiz 4 by email. The saxophone portion of the lecture was interesting and unexpected... putting more air through your instrument may improve the overall tone, though my instrument was bassoon, so I can't say much about single-reeds. Supporting the air column and maintaining consistent air pressure is important, though. Is it a soprano or an alto sax that you own?

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    1. It is my son Max, and he has both. Thanks for the comments!

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  18. Reviewed lecture 4 and submitted the pdf quiz via canvas.

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  19. Lecture 4 reviewed and quiz submitted via email.

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  20. Lecture viewed and PDF quiz e-mailed! Thank you!

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  21. Lecture 4 video and quiz are complete

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  22. reviewed lecture, submitted quiz.

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  23. lecture reviewed, quiz submitted

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  24. Many thanks for the blog comments, the questions, and the PDF quizzes.

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  25. Lecture watched and submitted on time. initially forgot to comment

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