Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. It is primarily concerned with the arrangement of electrons around the nucleus and the processes by which these arrangements change. This includes ions as well as neutral atoms and, ...

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Orbital magnetic moment versus Biot-Savart law

In atomic physics, the fine structure of spectral lines assigned to atomic hydrogen has always been explained by considering an orbital magnetic moment of atomic electron. Still this concept is ...
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60 views

Is there such a thing as an interaction radius for molecules?

My question is about estimating the radius of influence between two molecules; picture some mixture, comprised of water, oxygen gas (in small concentrations) and a molecule we denote $G$. In the ...
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157 views

In how many possible ways can a photon be emitted?

I am currently studying atomic physics, and I encountered the question above. I am posting this question because I can't afford to move on with even the tiniest bit of uncertainty in my understanding ...
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63 views

Ritz Variational Method

I want to use the Ritz Variational method to find a good approximation ground state and ground state energy for the hydrogen atom. For that purpose I take two different ansatzes, do the machinery of ...
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42 views

How does an electron manage to constantly revolve around the nucleus of an atom forever? [duplicate]

When an electron revolves around the nucleus of an atom is it using any energy in doing so. If so, where does this energy come from and how does it be a constant source (the electron revolves ...
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38 views

Need verification: Hamiltonian formulation states that an atom is bounded to an eigenenergy state due to opposing kinetic and potential energy

I received an explanation from someone who said that electrons in an atom are trapped in an eigenenergy state $E_n$ as per Hamiltonian mechanics is because the KE and PE of the atom balances ...
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596 views

Does the energy of ground and/or excited states have uncertainty?

In this question about absorption of continuous energies by discrete atom states, one of the reasons given to explain the width of spectral lines is the uncertainty principle (natural broadening): the ...
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30 views

Electron orbitals and the circular membrane vibrations

I just stumbled across the fascinating analogy between electron orbitals and the fundamental waves of a circular membrane in Wikipedia. Now the weird and arbitrary looking orbitals don't look so ...
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175 views

Unknown magnetic moment of orthohydrogen

Conforming to present atomic physics, the two elementary particles in hydrogen atoms can have either parallel or antiparallel magnetic moments, and the energy differences between these two kinds of ...
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154 views

How did we come to know that electrons actually 'move' in an atom?

Rutherford's experiments confirmed the existence of light-weight electron clouds in a mostly empty atom, and that they occupy some space around the nucleus. What made us conclude that they can move? ...
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160 views

Quantum mechanics,and how the law $ΔxΔp≥ℏ/2$ explains the paradox regarding atoms [duplicate]

In Chapter 2-3,Vol I of the Feynman lectures, Feynman talks about a rule in quantum mechanics that says that one cannot know both where something is and how fast it is moving. That the uncertainty of ...
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59 views

Effects of pressure rate of change on the temperature of a fixed amount of gas

In Vol I,Chap 1-2 of the Feynman lectures on Physics,Feynman talks about how a change in pressure of a fixed amount of gas enclosed in a piston can cause its temperature to increase/decrease. He ...
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44 views

Deriving X atom from Y atom

I want to know that, is there a possibility of deriving an atom of one element from another element? I knew it is done in the Sun, by the process of nuclear fission. If so, why didn't scientists tried ...
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127 views

Interpretation of Orbital Magnetic Moment

The wavefunctions for atomic orbitals have always been described to me one of two ways: As a "smeared out" electron standing wave with integer number circumference of de Broglie wavelengths As a ...
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96 views

Hydrogen 2p3/2 -> 1s1/2 transition polarisation and angular distribution

Could you please help me. I have to calculate the intensity angular and polarisation distribution in hydrogen electric dipole transition $\text{2p}_{3/2}\rightarrow \text{1s}_{1/2}$. To do this I ...
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1answer
192 views

Charge on the remaining atom after Alpha decay

In radioactive alpha decay, a helium atom is shown to be released. However, I was told that only thing released is a helium nucleus. If so, then it should leave two of its electrons in the atom ...
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99 views

Magnetic quantum numbers - axes correspondence

We know that the magnetic quantum number describes the space orientation of an orbital within an atom. For the $p$-orbital, the magnetic quantum numbers can be -1,0,1 (one for every axis). We have ...
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179 views

Why are the quantum numbers $n$ and $\ell$ denoted with those letters?

We have 4 quantum numbers: principal, azimuthal, magnetic and spin (denoted $n$, $\ell$, $m$ and $s$ respectively). I assume $m$ and $s$ are simply the initials of 'magnetic' and 'spin'. Is there any ...
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320 views

Do electrons pop into and out of existence around the nucleus of an atom?

What surrounds the nucleus is the probability wave. But are the electrons constantly popping in and out of existence around the nucleus in the cloud?
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34 views

Gain of entropy

Can we really interpretate third thermodynamic law as unconditional gain of entropy of closed system? For example, when they separate U 235, they drive the mix on the pressure barrier, so heavier U ...
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84 views

Is it possible to single out a proton, electron, neutron?

I've read that it's nearly impossible to take a proton from an element. But if it's "nearly" impossible then it is possible to some degree. If this has happened, what is exactly the process of taking ...
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1answer
43 views

Dipole approximation in solids

I have seen the use of dipole approximation (where the extent of the wave function is assumed to be much smaller than the wavelengths of the transitions or that of the electromagnetic field applied) ...
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1answer
152 views

DFT Calculations, Atomic Ionization Potentials — Which Exchange-Correlation Functional to Use, to Preserve Koopmans' Theorem?

I have a program which can perform density-functional calculations for atoms, given a density functional. Of course the simplest form of exchange potential to use is one relevant for a uniform ...
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164 views

How do I calculate the most probable orbital an electron is in?

If I saw a snapshot in time of an electron near a proton (Hydrogen), then the electron can be in any orbital as long as it doesn't lie on a node of the wave function. So how would I determine which ...
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43 views

How to derive the electron dipole selection rule in coupled bases?

We need to find $| \psi_f \rangle$ fulfilling the condition that $$ | \langle \psi_f | \mathbf{x} | \psi_i \rangle |^2 \neq 0.$$ When using the uncoupled bases $| l,m,m_s \rangle$ I can derive the ...
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1answer
59 views

Should it really be called “valence *sub*shell”?

The Wikipedia article on electron shells states this, which I (a chemical layman) also always assumed: The electrons in the outermost occupied shell (or shells) determine the chemical properties ...
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What is the potential between two hydrogen atoms in the spin-triplet state?

Take the Born-Oppenheimer approximation. Assume the two electrons are in the spin-triplet state. How does the potential between two hydrogen atoms look like?
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801 views

Why do we use the Coulomb potential for the hydrogen atom?

When solving the Schrodinger equation for the hydrogen atom, the Coulomb potential $V = \frac{e^2}{4 \pi \epsilon_0 r}$ is used. The Coulomb potential comes from classical electrodynamics, so why ...
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111 views

How can we prove that the shape of atom is spherical? [closed]

i am looking for a derivation that can prove that the shape of an atom is spherical . I experimentally proved this statement but i need a theoretical way.
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Why is Graphene Transparent?

Graphene is always in the news now a days and its key features are that it is; very strong, conductive and transparent. It is so transparent that each layer of graphene will only absorb 2% of Light ...
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113 views

Why is Graphene So Strong?

There has been a lot of news about Graphene since its discovery in 2004. And as we are all told it is a revolutionary material which is very strong, conductive and transparent. But what is it about ...
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45 views

photon absorption and emission

I was reading a book (Sears Zemansky) about this subject but I didn't understand something of an example, and this is that according to me there should be a process of emission for each of absorption ...
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31 views

What's the elementary reason for the formation of a band gap?

Bohr's solution for an isolated hydrogen atom showed that there are only discrete allowed energy levels, $E_n = -{E_0\over n^2}$ and the solution of the Schreodinger equation provided a certain ...
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70 views

How does An Electric Field Create a Dipole Moment of a Rydberg Atom?

I know that an Rydberg Atom will not usually have a Dipole Moment - as the positive nucleus are surrounded by a negative electron cloud, so there is no uneven charge distribution. However, I also ...
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46 views

Why Do Stark Manifold Graphs All Have Negative Energy?

I have been studying Rydberg-Stark State Atoms and their Stark Manifolds (like the one on Wikipedia: http://en.wikipedia.org/wiki/File:Hfspec1.jpg) and I was wondering, Why does the y-axis (of Energy ...
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31 views

Where can I find a list of approximate excitation energies?

I would like to know the excitation energies for the known states of various nuclides. Is there a list somewhere that has this documented? I can't seem to find them easily for many nuclides. Maybe I ...
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67 views

How does a electron revolve in Rutherford's model? [duplicate]

How can an electron revolve in a circular orbit because circular motion is an accelerated motion and acc. charged particle is a source of E.M. Wave. So,it should radiate out energy and hence would ...
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48 views

Are there materials with more than two states that can be used in circuit design? [closed]

Are there atoms or materials that have 3 or more states that can be used in circuit design? Can you provide any examples of such materials, and their possible applications to circuit design? And is ...
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How did Rutherford's gold foil disprove the plum pudding model?

What stops one of the two following scenarios from happening, consistent with the plum pudding model? The $\alpha$ particle, attracted by the electrons on the outer shell of the pudding, orbits ...
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4answers
2k views

Does the mass of an electron change with its “energy state”?

When an electron absorbs a photon, it gets into a higher energy state and goes into the upper orbit/shell. Does (rather should) this absorption of energy also have an impact on its mass (although ...
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2answers
127 views

Electron gas in metals: more like a liquid?

I'm trying to form a figure in my head about how electron bindings look like in metals. The electrons in metals can move freely, as opposed to their pair-bindings in molecules, and form what is often ...
2
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1answer
104 views

Why anomalous Zeeman effect is more common? [closed]

Why anomalous Zeeman effect is more common? Gone through many books, searched on Google, but couldn't find the answer.
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2answers
81 views

Does electron in an $s$-orbital have angular momentum?

I've read on science forum that electron in orbital $s$ has no angular momentum and would fall into nucleus, so hydrogen atom would not be possible. Electron has mass and speed after all right? So how ...
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4answers
1k views

Are atoms made of protons, electrons and neutrinos?

If neutrons decay into proton, electron and (anti)neutrino of electron type, then is it safe to say that atoms are protons, electrons and neutrinos?
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3answers
313 views

Do atomic orbitals exist in a fully ionised atom?

Say a H atom is ionised and then it captures a free electron at a later time, do the atomic orbitals then have to go through a transitory phase to accommodate the electron before they form the correct ...
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21 views

Excitation probability given pulse bandwidth and atom linewidth

Consider photon source producing photon pulses with a frequency distribution $f(\omega)$ and a glass tube filled with a gas. The atoms of the gas can be excited by photons with a frequency of ...
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1answer
537 views

Difference between a hydrogen ion and a proton

I've run into a bit of a problem on this weeks coursework. A proton and an electron initially at rest combine to form hydrogen. Find the wavelength of the emitted photon? So, as far as I can ...
2
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2answers
392 views

Why are neutrons present in an atom? [duplicate]

I have a very stupid question perhaps, but please answer me. An atom consists of electrons, protons, neutrons. protons are positively charged and electrons are equally negatively charged. The charge ...
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27 views

Photo-excitation in terms of particle physics [duplicate]

How does a photon couple to an electron during an excitation/de-excitation process in an atom? My current understanding is rather limited especially when considering types of fundamental forces and ...
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1answer
25 views

Is it more difficult to create higher energy photons, given there is excess available energy?

Im not talking about pair production, I mean a single photon created from an energy transition between two electron shells. I'm studying K(alpha) and K(beta) fluorescence transitions in metals, and ...