I apologize if this is an obvious question, but I can't find the answer anywhere. In this page: http://ie.lbl.gov/education/parent/U_iso.htm are listed the isotopes of Uranium. Some of them, for example U238 are listed many times, with "m1" or "m2" attached to the mass number. What does this mean?
Asked
Active
Viewed 75 times
1
-
4Quick Google search led me to wikipedia's article on metastable isomers. Notation is given there. – Kyle Kanos Jan 18 '14 at 17:00
-
Thank you! I used google too and found nothing... weird. – carllacan Jan 18 '14 at 17:23
1 Answers
1
These "metastable states" are excited states of the nucleus that have a non-trivial lifetime (most nuclear excited states decay very quickly).
-
2I just can't resist adding the truly remarkable example of why not all metastable states decay quickly: Tantalum-180m. It's the only naturally-encountered excited nucleus present in macroscopic quantities on Earth, and it is stabler than its ground state by an incredible factor of at least $10^{18}$. – Nicolau Saker Neto Jan 18 '14 at 20:36