An unique anomalous decay Q(β+)<0

[kiwaho]

Normally 87Rb can decay to 87Sr because Q(β-)= 282.2keV in a half life of 4.97*10^10 years.
But do you know 87Sr can also decay back to 87Rb by EC(Electron Capture) in a very short half life 2.815 hours by a little chance of 0.3%?
Of course, the reverse decay can not happen naturally, because Q(β+)= -Q(β-) = -282.2keV < 0, the only condition is that 87Sr should be excited to level of 388keV with spin-parity 1/2-.
This example is so unique!
I am wondering if this bi-direction decay phenomenon could apply to any other isotopes?

 

[AndyW]

Thank you for bringing this interesting phenomenon to my attention. I am always intrigued by rare and unique occurrences in nature. In response to your question, yes, this bi-directional decay phenomenon can occur in other isotopes as well.

In fact, this type of decay, known as double beta decay, has been observed in several other isotopes such as 130Te, 76Ge, and 136Xe. In these cases, the decay can occur through both beta-minus and beta-plus decay, depending on the energy levels and spin-parity of the isotopes involved.

In addition, there are also cases where the reverse decay, from the daughter isotope back to the parent isotope, can occur through other processes such as electron capture or internal conversion. These types of decays are often very rare and require specific energy levels and spin-parity conditions to be met, just like in the example you mentioned with 87Sr and 87Rb.

Overall, the bi-directional decay phenomenon is a fascinating and complex aspect of nuclear physics that continues to be studied and understood by scientists. Thank you again for bringing this to my attention and I hope this has answered your question.