Mod-01 Lec-42 Mossbauer Spectroscopy

So, in the previous lecture we talked about how elements are synthesized inside the core of star and we reached up to that 56 iron region ironical region where the binding energy per nucleon is highest and then further fusion is not energetically favorable. But we do have elements much beyond that; all gold and silver and many things beyond that, uranium.

So, how these elements are formed how these nuclei are formed and then we talk little bit about that; that is the neutron which can sneak into these stable nuclei and make higher and higher isotopes and from there one can get these bigger heavier elements. So, today we will discuss the synthesis beyond that iron nickel region and then maybe we

will talk also of some applications. So, I will go to screen. So, here is the process. Suppose, supposing that neutrons are present and from where the neutrons are coming? Some stray reaction that we talked; normally reactions proceed through alpha particle capturing but then, there are some stray reactions we are once in a while

a neutron is produced. So, in the core of the star you do have some neutrons and at one place if a neutron is produced maybe after many many years, hundreds of years or 50 years a second neutron will be produced there because these neutron producing reactions are rare, but neutrons are there. So, look at your screen suppose, we start

with this iron 56 and a neutron just sneaks into it. If that happens, it will make iron 57 and iron 57 is a stable nucleus will stay there and then after many many years another neutron comes and that also goes into this 57 iron and then it will go to this 58 iron.