All Questions
Tagged with quantum-chemistry electronic-configuration
96
questions
-2
votes
1
answer
81
views
Why do we only use the principal quantum number to calculate the energy of an electron in an H atom? [duplicate]
According to my high school textbook the energy of an electron in a hydrogen atom is $E = -13.6/n^2~\pu{eV}$, where $n$ is the principal quantum number of the orbital in which the electron is present.
...
0
votes
1
answer
47
views
Why we seldon use Fermi Surfaces to explain chemical behaviour? [closed]
Chemistry basically involves studying the behavior of electrons in atoms and their consequences. Solid-state physicists deeply study Fermi surfaces, analyzing the three-dimensional behavior of atoms. ...
- 224
1
vote
1
answer
92
views
Does ionisation change the physical/chemical properties of an atom?
From what I have learned, the number of electrons on the outermost shell (called the valence electrons), determines the chemical properties of an atom, this is why elements in the same group have ...
- 35
4
votes
1
answer
272
views
Eigenfunctions of total angular momenta as linear combinations of Slater-determinants
In the Hartree scheme for many-electron atoms, the approximated Hamiltonian (in a.u.)
$$\hat{H} = \sum_{i=1}^Z \left(-\frac{1}{2} \nabla_i^2 -\frac{Z}{r_i} + V_\text{H}\left(r_i\right)\right)$$
is ...
- 41
4
votes
1
answer
279
views
Principal quantum number and 'good' quantum numbers
When we discuss about configurations we specify n, l, m quantum numbers for the individual electrons.
My question is: why when we pass from configurations to atomic terms in order to use the total ...
- 101
1
vote
0
answers
59
views
How can one obtain the same-spin and opposite-spin terms of the MP2 energy by integrating out the spin?
Just as specified on the psi4 website here: https://psicode.org/psi4manual/master/dfmp2.html, the Moller-Plesset Perturbation Theory states that the second order correction to the ground state energy, ...
- 11
1
vote
1
answer
90
views
On the energies of molecular orbitals
I found a useful (though simplified) scheme illustrating the energies of atomic orbitals, in crescent order:
I wonder if there was an analogous (simplified) scheme or rule for molecular orbitals, at ...
- 119
-2
votes
1
answer
127
views
How can Planck’s equation and the wave equation simultaneously coexist with contradicting each other? [closed]
The equations:
E=hf (Planck’s equation, where E is the energy, h is the Planck’s constant and f is the frequency) and
V=fλ (where v is the speed (in a vacuum), f is frequency and λ is the wavelength) ...
- 422
2
votes
0
answers
88
views
Hartree Fock calculations on F2 don't match the traditionally taught MO diagram
I ran some Hartree-Fock calculations on F2 to visualize the MOs, and the energy levels don't match the trend commonly taught (shown here: https://chem.libretexts.org/Courses/...
- 21
-1
votes
2
answers
482
views
Why is the d subshell only stable when all of its orbitals are filled? [closed]
I was learning about the Aufbau principle and quantum electronic configuration. Here are some of the yet-unanswered queries that I wish to know the answers to.
I discovered that the d subshell is ...
- 293
-2
votes
2
answers
789
views
Why silicon doesn't have the electronic configuration [Ne] 3s¹ 3p³?
I have read that half or fully filled orbitals provide more stability to the element due to symmetry and exchange energy.It is the reason for electronic configuration of Cr-[Ar]4s¹3d⁵.
Then, why doesn'...
- 1
-1
votes
1
answer
53
views
Analog of chemical accuracy in vibronic energy calculation [closed]
Is there any analog of chemical accuracy in vibronic energy calculation? I understand that the unit is /cm however, probably, I shouldn't expect a given number in that unit as the analog.
I am ...
- 245
6
votes
3
answers
2k
views
Why are there so many metals in the periodic table?
Brief Background: I was studying about the 'classical electronic configuration' of the first 20 elements of the periodic table today and was bewildered by the fact that there are an equal number of ...
- 293
3
votes
1
answer
671
views
Fundamental doubts about energy levels vs. shells vs. subshells vs. orbitals
First in school I learnt that when supplied enough energy, the electron in a hydrogen atom will jump energy level(s), denoted by $n=1$, $n=2$ and so on for integral values of $n$. Then I learnt about ...
- 521
2
votes
0
answers
36
views
How do the spin-matrices change in systems without spherical symmetry?
The (non-relativistic) spin matrices of a free electron, with $z$ as the quantization axis, read:
$$
\boldsymbol{S}_{x}=\frac{\hbar}{2}\left[\begin{array}{ll}
0 & 1 \\
1 & 0
\end{array}\right],...
- 181