All Questions

Filter by
Sorted by
Tagged with
2
votes
1answer
54 views

Can the spectra of helium atom be solved by Schrodinger equation?

Can the Schrodinger equation work out the spectra of helium atom, not all, but part of them?
1
vote
0answers
46 views

Has man ever observed the spectrum of a single hydrogen atom?

Were there this kind of experiment done before? The spectrum we observed is radiated by huge number of hydrogen atoms in the gas, not by single hydrogen atom. I know it's very hard to test a single ...
-1
votes
2answers
181 views

Why Bohr atom model is still being tought in high school? [duplicate]

Bohr atom model is still the textbook content of today's high school physics. We all know that the Bohr model is only suitable for single electron hydrogen atom, not suitable for other atoms. For ...
10
votes
1answer
1k views

Why don't all electrons contribute to total orbital angular momentum of an atom?

There are 47 electrons in a Silver atom, but talking about its orbital angular momentum we only take the outermost valence electron which occupies the 5s orbital. Why don't the remaining inner 46 ...
1
vote
0answers
25 views

How to calculate orbital densities/shapes of atoms in 3D?

When we read about orbitals, I'm sure we are all used to seeing illustrations of them by drawing some contour "along" the probability density function so that the electron's position is equiprobable ...
3
votes
1answer
32 views

Neutral lithium ionization energy for removing an electron from the $1s$ orbital

How much energy does it take to singly ionize a neutral lithium atom by removing an electron from the $1s$ orbital?
3
votes
1answer
75 views

In chemical compounds, where does the “magic” come from in atomic “magic numbers”?

It is well known that atoms with a full electron shell are more stable, it is one of the first facts taught in a middle school Chemistry course: "An element whose atoms have no electrons outside ...
1
vote
1answer
58 views

What is so special about Paschen, Balmer and Lyman series?

I'm reading McIntyre's QM book and I see the same diagram ever so often: He goes on to say: I don't understand what he is trying to say with the last sentence. It seems he is saying, that ...
2
votes
2answers
116 views

Why do electrons revolve around the nucleus? [duplicate]

Why do electrons revolve around the atom's nucleus? Where does it get the energy for the revolution? Do the electrons stop revolving at absolute zero temperatures?
2
votes
0answers
34 views

What are the prerequisites for a free electron and an atom/ion to recombine?

I'm mostly interested about recombination not in plasma (e.g., recombination of beta particles with atoms that they pass by), although the rules are probably the same. Say, there's a free electron ...
1
vote
3answers
132 views

Shape of orbitals in atoms with multiple electrons

I found this statement when browsing the Wikipedia article for atomic orbitals: "Orbitals of multi-electron atoms are qualitatively similar to those of hydrogen." Is this true? Googling around I ...
21
votes
3answers
3k views

When an electron around an atom drops to a lower state, is 100% of the energy converted to a photon?

Let's say we have an electron around atom. Let's say the electron drops into a lower electron shell. Is 100% of the energy difference converted to a photon? Does the atom recoil at all? Is the any of ...
1
vote
1answer
48 views

Atomic model - absorption [duplicate]

I have a question regarding the absorption of light in e.g. hydrogen atoms: I didn't quite understand how the electron knows that it can only absorb photons of the right energy. I thought that when ...
0
votes
0answers
19 views

Question about Electric Dipole Transition Selection Rules [duplicate]

I learned that the selection rules for electric dipole transition in a hydrogen-like atom is \begin{align} \delta l & = \pm1 \\ \delta j & =0,\pm1 \\ \delta m_j & =0,\pm1 \end{align} I ...
0
votes
0answers
10 views

Aufbau principle and quantum number $n$ (Bohr) [duplicate]

When we have to check the energy of electron we look for $n+\ell$ as in filling of electrons A/t aufbau? Or is just simply higher then value of $n$ then more the energy of electron? Because when we ...
0
votes
2answers
31 views

How many pions can be accomodated in an orbital?

electrons have a spin of 1/2 and 2 electrons are accomodated in an orbital pions have a spin of 0 so how many pions can be accomodated in an orbital? i thought that since no two electrons (or pions) ...
0
votes
2answers
72 views

Orbital angular momentum quantum numbers - subtracted?

Reading Griffiths' Quantum Mechanics. We have the electronic confirmation of Carbon as $$(1s)^2 (2s)^2 (2p)^2$$ in the ground state. He says There are two electrons with orbital angular ...
0
votes
0answers
19 views

How to use Dyall basis sets for radial wave functions?

I have found the dyall basis set coefficients on the homepage http://dirac.chem.sdu.dk/basisarchives/dyall/ Does anyone in the forum has experience for using for example the "5p" basis set? I only ...
7
votes
2answers
650 views

Probabilities in non-stationary states

I'm confusing myself. Let's represent some state in the eigenbasis for Hydrogen: $$|\psi\rangle = \sum_{n,l,m}|n,l,m\rangle\langle n,l,m|\psi\rangle.$$ Now denote the initial state by $\psi(t=0)\...
1
vote
1answer
46 views

Why does a stable orbit of $H$ atom contain an integer number of de Broglie wavelengths? [duplicate]

I was trying to understand why a stable orbit of a hydrogen atom has to satisfy that the orbit length must be a multiple of de Broglie wavelength. I have seen some related questions like This. But ...
1
vote
3answers
147 views

Is the $2p\rightarrow2s$ transition possible?

Selection rules in one electron atoms are: $\Delta n=$ any $\Delta l=\pm1$ $\Delta m_l=0,\pm1$ $\Delta s=0$ Parity must change Under strong spin orbit interaction: $\Delta j=0,\pm 1$, but $j=0\...
0
votes
0answers
12 views

Spectroscopic notation for $As$

I’m wondering if I’m approaching hund’s Rules for Arsenic correctly (Ar): (Ar)$(3d)^{10}(4s)^{2}(4p)^{3}$ I started with HR1: Maximize the spin. I have 6 orbitals so I can put one electron in the ...
2
votes
0answers
84 views

Why do nodes exist in wavefuncions of electrons? [duplicate]

Nodes are points in space around a nucleus where the probability of finding an electron is zero. However, is there a reason for the existence of Nodes? I'm looking for an intuitive explanation if ...
0
votes
2answers
46 views

Generating random position for electron within 3D orbitals

Apologies in advance if this is the wrong StackExchange to ask this question in... if it is not, please don't just down-vote, let me know where else to go and I will gladly. I'm just trying to learn. ...
1
vote
0answers
60 views

When will Hund's rules fail?

I heard someone mentioned that Hund's rules do not always work. Looking at atomic spectrum: (https://qudev.phys.ethz.ch/phys4/PHYS4_lecture10v1_2page.pdf page 10 Hg spectrum) How could singlet (with ...
1
vote
1answer
77 views

What does degeneracy and multiplicity in Term symbol mean?

$^{2S+1}L_J$ was the term symbol. I watched a video online saying $2J+1$ was the fold of degeneracy to the term symbol. Specifically, for nitrogen, the term symbol for the lowest energy was $^4S_{3/...
0
votes
2answers
38 views

Why does 'The electron density builds quadratically with distance from the nuclues.'?

I found the statement above on this useful website. http://photonicswiki.org/index.php?title=Atomic_Orbitals_and_Nodes But I am confused. Why would that be the case? Is this based on some exotic ...
3
votes
0answers
49 views

How come the xenon $6s$ state is metastable?

I'm having some trouble puzzling out some aspects of the electronic excitation spectrum of xenon, and I'd appreciate some help with it. This classic paper ─ the first one to pioneer the use of laser-...
0
votes
0answers
18 views

$\langle r \rangle$ and orbital energy [duplicate]

Even though $\langle r_{2s} \rangle > \langle r_{2p} \rangle$ based on the following formula $$ \langle r_{n\ell} \rangle = \frac{{a}_{0}}{2}(3{n}^{2}-\ell(\ell+1)) $$ $2s$ has a lower orbital ...
2
votes
1answer
74 views

What happens to the $3d$ and $4s$ levels during the ionisation of a transition metal?

I'm just wondering about the transition state of a transitional metal before (ex: $[\mathrm{Ar}]\, 3d^3 \,4s^2$) and after ionisation (which means $[\mathrm{Ar}]\, 3d^3 \,4s^1$) because before ...
0
votes
1answer
158 views

Must the total orbital angular momentum quantum number $L$ be less than the principal quantum number $n$? If so, why?

I am studying LS coupling and term symbols. In my textbook, there is an exercise: Why is it impossible for a $2\ ^{2}\text{D}_{3/2}$ state to exist? The answer says, the total orbital angular ...
0
votes
0answers
20 views

Understanding the radial distribution function [duplicate]

I am confused why the maximum of the radial distribution function for 2p orbital is closer to the nucleus than that for 2s orbital. Doesnt this mean that there is a higher chance of finding 2p orbital ...
0
votes
1answer
202 views

How to get the radius of Bohr from the uncertainty principle?

I would like to know how to get the following result: \begin{eqnarray} a_0=\frac{4\pi\varepsilon_0 \hbar^2}{\mu e^2} \end{eqnarray} from the beginning of the uncertainty of heisenberg. If possible, I ...
4
votes
3answers
352 views

Would an $H_2O$ Molecule actually look like this 3D representation if we could see it?

I'm trying to get a much better grasp on atoms and molecules and I am a visual learner. I found the above image here. This intuitively makes sense to me because I can see how the electron orbitals ...
0
votes
1answer
70 views

Can electron jump from $n=2$ to $n=3$?

Assume Bohr's Model. Lets not consider latest modern theory. Consider a Hydrogen atom in ground state (n=1). It excites to next level n=2. It will stay here for 10^-8 seconds. Now we supply more ...
0
votes
0answers
48 views

Term Symbols of Carbon Atom [duplicate]

For a neutral Carbon Atom, the electron (ground) configuration is $1s^2$$2s^2$$2p^2$. I am told that the term symbols $^{3}S_{1}$ and $^{3}D_{1,2,3}$ are forbidden by Pauli Exclusion Principle. May ...
0
votes
2answers
42 views

Force to step down atomic level of an electron?

How much force is needed to step down atomic level of an electron? Where does it gets it energy to overcome the orbits to step up?
3
votes
1answer
40 views

Why does $2p$ have highest RDF at $4a_{0}$?

I was reading notes from my first class in Quantum Physics that I received and left confused at the following statement: For each principal quantum number $n$, the orbital set with the highest $\...
0
votes
0answers
78 views

Quantum numbers $n$ and $\ell$ relation in many electrons atom [duplicate]

Solving the Schrodinger equation for hydrogen atom we arrive to the conclusion that quantum numbers $n$ and $\ell$ have the relation $$\ell=0,1,...,n-1.$$ Now,since we can not solve the Schrodinger ...
0
votes
1answer
39 views

Electronic configuration

In chemistry the lithium electronic configuration is $$1s^22s^1 \, .$$ Can we prove this using approximation method like perturbation theory that this the ground state and not for example $1s^22p^...
1
vote
1answer
36 views

Given the wavefunction of an electron in hydrogen, what possible energies can it obtain and what are the probabilities of those energies? [closed]

we are given, $$\psi(\textbf{r})=A\left[R_{2,1}(r)Y_{1,-1}(\theta,\phi)+iR_{2,1}(r)Y_{1,0}(\theta,\phi)+2R_{2,1}(r)Y_{1,1}(\theta,\phi)\right]$$ we can rewrite this as: $$\left|\psi(\textbf{r})\right&...
2
votes
1answer
82 views

Ground state of Beryllium (${\rm Be}$)

Why is the ground state of Beryllium (${\rm Be}$) with electronic configuration $[{\rm He}]2s^2$ is $^1S_0$ and not $^3S_1$? The state $^3S_1$ has higher spin multiplicity.
0
votes
2answers
88 views

Do empty orbitals have energy?

Suppose we have the Na (Sodium) atom. It has half-filled the 3s orbital and unfilled 3p orbital. Does the empty 3p orbital have energy? also does the energy of 3p change if an electron occupy it?
0
votes
2answers
61 views

How are line spectra explained after rejecting/improving Bohr's theory?

I learned that Bohr explained line spectra by postulating that electrons can only be at certain discrete distances from the nucleus. Later, this theory was refuted/improved by de Broglie and ...
-1
votes
3answers
288 views

What does the principal quantum number really mean? [closed]

What do principal quantum numbers actually represent? The modern structure represent that electrons do not revolve around the nucleus. It says there are no shells or orbits for electron rather there ...
1
vote
1answer
214 views

Electron transitions and spin [closed]

Take a single proton and electron. Write $n,\ell,m$ for the quantum numbers of the electron, and $1/2$ or $-1/2$ for its spin. The space of states of this system is the separable Hilbert space $V$ ...
0
votes
1answer
49 views

State with highest energy of Carbon atom

A possible excited state of the $C$-Atom is one with a $3s$ electron: $(1s)^2(2s)^2(2p)^1(3s)^1$. One can find out that there are the 4 possibilities $^1P_1, ^3P_2,^3P_1,^3P_0$. Why is the $^1P_1$ ...
4
votes
4answers
336 views

How do orbitals exist in an atom?

I have come across a picture online which talks about 1s,2s,2p orbitals of a sodium atom. Observation:In the picture we see some volume of space in common to two orbitals. For example:The circled(...
1
vote
1answer
71 views

How can an ion ever capture an electron if an electron requires a precise momentum to match a subsequent orbital?

Suppose an electron approaches a proton with greater energy than the hydrogen ground state. Will the electron scatter? If so, how could an electron ever be captured given it would require exactly the ...
0
votes
1answer
51 views

What effect causes energy difference between $2 \:^1 S$ and $2\: ^1 P$ electron state in a helium atom

I'm wondering where the energy difference between the two electron states $2 \:^1 S$ and $2\: ^1 P$ comes from in a helium atom. I thought it is the fine structure, but the fact that $S = 0$ is ...