Irreversibility is the basic principle of the Universe. It’s impossible to get back a reverse motion exactly. Everything is always different and new. Although at first glance it might look the same. Consider snowflakes, every roll of the dice. It is not possible to return to the past, but it is possible to change the future, just on the basis of the past.
See below a table. There are topics (considerations and suggestions) on the subject of this section. If you want, download the pdf file.
See below – the remarks waiting for word processing
Emission of photons from atoms – jump electrons to a lower level. See line spectrum. The line spectrum is not an ideal line, but a probabilistic distribution of radiated frequencies with a peak in the middle.
All frequencies are close together in a given probabilistic distribution. It can be assumed that each frequency is unique, unrepeatable. For the reason we know that we can insert an infinity of other numbers into the smallest interval on a number axis. Even each radiated frequency could be expressed by an irrational number – see the square root of two, or five, etc.
The defined difference df in radiated frequencies is not a fixed value, but a value changed in a given probability distribution. The same is valid for Planck´ constant.