We’ll need nuclei a lot in this course. Let us refresh our knowledge on what they are. After this video, you’ll spontaneously think about more than the obvious properties when you’ll hear the word nucleus.

Video 48 Min  + 2 Min read to complete

Next to its mass, charge and spin, the multipole moments of a nucleus are key properties. They tell how strongly and in which way the nucleus will interact with surrounding electromagnetic fields.

Video 48 Min  + 2 Min read to complete

download printable slides (3)
download printable slides (6)

There are two tasks related to this video:

1. Find one example (in daily life or in science) where multipole moments of any kind play a role. Write down that example in the forum underneath. Comment on the examples of your colleagues if you feel like.
2. You saw a few classical charge distributions in the video (a copy is here). For the left two of them, calculate the monopole, dipole and #02010 quadrupole moments. Write your answer in a pdf file (typed or #020101#8e43f0

 handwritten), and upload it via the ‘quiz’ button at the end. If you don’t know at all how to start, these 12 minutes of extra hints/explanations might be useful (optional video). If you feel like, you may attempt the third charge distribution as well (right-hand side of the picture), although that involves some math that is not the focus of this course.

All knowledge of mankind about nuclear moments, is tabulated in this online database (the same data in a more dynamic presentation are here). Feel free to browse through it. You may, for instance, try to find in the database the nuclear quadrupole moment and the magnetic dipole moment of the 245 keV level in ¹¹¹Cd.

Optional: you can read a blog text about this database, or you can read a scientific paper about it.

We can interact with nuclei by the radiation they emit or absorb. Just as we describe the shape of the nucleus by multipole components, the properties of the emitted radiation can be described in a multipole framework as well. We will need this to some extent in hyperfinecourse B, on experimental methods based on hyperfine interactions. The general concept is described in this video. If you want to dig deeper (optional), then the Wikipedia entry given under the video is a good start. 

Video 48 Min  + 2 Min read to complete

Optional text from Wikipedia to dig deeper: 

Not all nuclear multipole moments are different from zero. All odd nuclear electric multipole moments (dipole, octupole, …) are zero, and all even nuclear magnetic multipole moments (monopole, quadrupole, …) are zero as well. This video explains why:

Video 48 Min  + 2 Min read to complete

download printable slides (3)
download printable slides (6)

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