“Quantum leaps”: the “new” idea of energy transfers in the realm of subatomic particles

 

Isaac Newton (1643 – 1727) ’s pivotal ideas are emblematic in terms of the canonic protocols enthroned as mandatory tools for dealing satisfactorily with time and space along our daily interactions in the material world. But they were not able to bring under the main spot the energy transfer mechanism at the level of atomic realm.

The core problem was a behavioral inconsistency detected: the event’s disobedience to the classical mood of natural phenomena. Mean, it looked like no time was elapsed between, for example, irradiation and due energy transfer (action) and the respective particle animation (reaction). It looked like an instant process: elapsed time between action and reaction equals zero, what would be an impossibility according to the well-established classical world. Alternative visions were brought in among the various attempts to reconcile classics parameters with that weird behavior. Downing our eyes to look at one sole electron orbiting around its related atomic nucleus, we will pick up a “model” proposed by a Danish physicist named Neils Bohr (1885 – 1962) in 1913. A key argument in Bohr´s model was his conception of a “set of allowed (possible) values of energy levels (states) ...”. so that atoms would absorb or emit radiation only when the electrons abruptly jump between those “allowed” (or stationary) states. Direct experimental evidence for the existence of such discrete states was obtained (1914) by the German-born physicists James Franck and Gustav Hertz.

Well, it represented a radical departure from the classical mood we mentioned above.

Niels Bohr proposed a theory for the hydrogen atom, which is the simplest among all the atoms in universe, once it is composed by one electron orbiting around a positively charged atomic nucleus. His argument was based on the assumption that “some physical quantities only take discrete values”.

Well, I guess it is useful to point out here that immediately before 1913, an atom was thought of as consisting of a tiny positively charged heavy core, called a nucleus, surrounded by light, planetary negative electrons revolving in circular orbits of arbitrary radii.

In other words, electrons move around a nucleus, but only in prescribed orbits, and If electrons jump (a quantum leap) to a lower-energy orbit, the energy difference is sent out as radiation. In fact, those quantum leaps between two states are typically tiny, that it is precisely why they weren’t noticed sooner. Our focal point here is to stress that it happens so sudden, that many of the pioneers of quantum mechanics assumed they were instantaneous.

My dear human brothers and sisters, let us overact our words here and emphasize that due to these primary ideas set to reconcile theoretic flaws with standing or even outstanding scientific moods, the world evolved from, let’s say, a Morse Code based telegraph message transfer from point #1 to point # 2 two to nowadays satellite based world communication, since them.

Bohr’s model consists of a small nucleus (positively charged) surrounded by negative electrons moving around the nucleus in orbits. Bohr found that an electron located away from the nucleus has more energy, and the electron which is closer to nucleus has less energy.

Bohr organized his ideas under a set of postulates so to comprise a (complete?) model of an Atom: the postulates are:

• In an atom, electrons (negatively charged) revolve around the positively charged nucleus in a definite circular path called orbits or shells.
• Each orbit or shell has a fixed energy and these circular orbits are known as orbital shells.
• The energy levels are represented by an integer (n=1, 2, 3…) known as the quantum number. This range of quantum number starts from nucleus side with n=1 having the lowest energy level. The orbits n=1, 2, 3, 4… are assigned as K, L, M, N…. shells and when an electron attains the lowest energy level, it is said to be in the ground state.
• The electrons in an atom move from a lower energy level to a higher energy level by gaining the required energy and an electron moves from a higher energy level to lower energy level by losing energy.

 

Dears, let us meet again soon over here!

 

I am Mawo Adelson Adewale de Brito, a Voodoo priest, a physicist, a Professor with a MSc degree on “Impacts of Environmental Radon on Health”

 

References:

1.     Quantum Leaps, Long Assumed to Be Instantaneous, Take Time; https://www.quantamagazine.org/quantum-leaps-long-assumed-to-be-instantaneous-take-time-20190605/ (February 12, 2023)

2.     Enery fundamentas; https://home.uni-leipzig.de/energy/energy-fundamentals/01.htm (February 12, 2023)

3.     BYJU´S Bohr Model of an Atom; https://byjus.com/chemistry/bohrs-model/ ; (February 12, 2023);

4. Cover image: Neils Bohr; https://en.wikipedia.org/wiki/Niels_Bohr 

 

The frisson about quantum physics

 Let us use the regular classic physics jargon to describe a situation: Every time an “A person” is introduced to a “B person” and, by chance, they mention their individual professional status to one another, and it happens that “A person” says “I am a physicist”, so what follows next, invariantly, in case “B person” does not share any professional link or whatsoever association with that natural science? That “B person” goes freak in a matter of a millionth of second and asks:” Are you in quantum physics???”

At the end of the day, let us sigh out a breath of tranquility, sit down while sipping a glass of wine and go trying to set somethings about “quantum physics” under some rational history light.

Beforehand, let us put it out clear for once and for all that a quantum (a Latin word which plural is quanta) is the smallest discrete unit of a phenomenon. For example, a quantum of light is a photon, and a quantum of electricity is an electron. The word quantum comes from Latin, meaning "an amount". If something is quantifiable, then it can be measured.

Well, there are some interesting events we could bring here to help us shed simple non-mathematical light on some of the reasons the idea of energy quanta was brought in. We will pick the photoelectric effect, a study that ultimately claimed the 1921 Nobel Prize for Albert Einstein (1879 – 1955), who was not an enthusiast of “quantum physics”, despite of taking the quantum concept of energy to help explaining his theory on the above mentioned effect.

The problem: It was noticed that when electromagnetic radiation (like light for instance) is incident on a metal surface, transference of energy to the irradiated electrons occurs. According to classical physics a lag between irradiation and subsequent emission of some of the electrons would take place. But it simply does not materialize, because the transference happens “instantly”, in frontal contrast with the prediction by classical physics. Mean, there is not a “time lag” for the electrons to acquire the incident energy. In other words, emission takes place as soon as the light shines on the surface; there is no detectable delay.

Einstein defended that the energy transference is a function of the incident radiation frequency and its relation with the so-called frequency threshold of the metal surface. So, if incident radiation frequency is of a value below that threshold, it will not be able to promote electrons ejection from the metal surface. Looking at the practical aspects of the problem, Einstein moved to the conclusion that the energy transference occurs under the form of “unitary blocks” or “quanta”. And he extended the ad hoc relation fist devised by Max Planck to express quantitatively the amount of energy transfer: E = h 𝛎, where E is the energy, 𝛎 f its frequency, and h is the Planck’ s constant, given in the MKS as 6.62607015 × 10^-34 m² kg/s.

 

References:

1.     BYJUS; https://byjus.com/question-answer/why-photoelectric-effect-cannot-be-explained-by-the-classical-physics/ ; (accessed on February 10, 2023);

2.     Wikipedia; Albert Einstein; https://en.wikipedia.org/wiki/Albert_Einstein ; (accessed on February 10, 2023);

3.     https://socratic.org/questions/what-was-einstein-s-explanation-for-the-photoelectric-effect ; (accessed on February 10, 2023)