دانلود کتاب فیزیک نجومی

In general, nuclear transitions are almost independent of the atomic environment of the nucleus. This feature is a basic prerequisite for the widely used nuclear chronometers (with the most famous example of 14C, the so-called radiocarbon dating). However, a closer look at the details of nuclear transitions shows that under special circumstances the atomic environment may affect nuclear transitions. This is most obvious for electron capture decays where the nucleus captures an electron (typically from the lowest K-shell). A nice example for the experimental verification of this effect is the dependence of the electron capture halflife of 7Be on the chemical form of the beryllium sample .