Linked Questions

1 vote
2 answers
706 views

Why is up spin in the px orbital and down spin in the py orbital considered an excited state? [duplicate]

Why is this form of p orbital occupation an excited state? I understand that there should be one up spin and one down spin in one orbital box by Pauli's exclusion rule. But in the p orbitals, it doesn'...
underlush's user avatar
18 votes
6 answers
6k views

Why does the two-electron exchange integral in Hartree-Fock theory have positive values?

In Section 2.3.6 of Szabo & Ostlund's Modern Quantum Chemistry, the exchange integral has the form of $$\int \mathrm{d}\mathbf{r}_1\,\mathrm{d}\mathbf{r}_2\, \psi_a^*(\mathbf{r}_1) \psi_b(\...
Molec's user avatar
  • 181
33 votes
2 answers
8k views

What is the exchange interaction?

As the wikipedia article for the exchange interaction so aptly notes, exchange "has no classical analogue." How wonderful. Exchange shows up essentially while enforcing the condition that two ...
jheindel's user avatar
  • 13.1k
16 votes
2 answers
26k views

Why are full and half filled orbitals the most stable?

Why are degenerate orbitals (restricted to a single spin) less stable when neither fully filled nor completely empty? Why, in most molecules, are half-filled and fully-filled shells more stable than ...
Niels Kornerup's user avatar
15 votes
1 answer
2k views

Why doesn't ionization energy decrease from O to F or F to Ne?

I know that in general, the first ionization energy increases across a period due to increasing nuclear charge, reasonably constant shielding & decreasing atomic radius. From N to O, however, the ...
Vulgar Mechanick's user avatar
10 votes
1 answer
40k views

How do I find the ground state term symbol for transition metal complexes?

I have a problem where I'm trying to match metal complexes with the proper ground state term symbol. I've tried doing a Google search and looking for a process, but haven't had any luck. I decided ...
MattyT's user avatar
  • 355
12 votes
1 answer
15k views

Derivation of the Orgel diagram for octahedral d2 complexes

The Orgel diagram for a typical octahedral $\mathrm{d^2}$ complex is shown below: (source: Kettle, Physical Inorganic Chemistry, p 146) I understand that the right-hand half of the graph shows how ...
orthocresol's user avatar
  • 71.4k
12 votes
2 answers
1k views

Hartree-Fock dipole moment

I read this sentence in a paper (J. Phys. Chem. A 2014, 118 (20), 3678–3687. DOI: 10.1021/jp502475e): Calculations using Hartree–Fock theory systematically overestimated dipole moments and ...
James LT's user avatar
  • 977
-2 votes
1 answer
5k views

Half-Filled Shells and Stability explanation [duplicate]

I am reading a book about Advanced Chemistry, and it is discussing the subject of half-filled orbitals. The book notes that Chromium has an electron structure of $1s^2 2s^2 2p^63s^23p^63d^54s^1$ ...
vik1245's user avatar
  • 1,230
4 votes
1 answer
1k views

Volume of orbitals

As I was learning about atomic structure, the lecturer made a seemingly dubious claim: The volume of a p orbital is one-third that of the s orbital. Thus, inter-electronic repulsions are ...
Tan Yong Boon's user avatar
3 votes
1 answer
768 views

Do electrons of opposite spin attract each other? [closed]

Electrons of opposite spin create magnetic fields that are opposite to each other. So, is it possible that, 'such electron pairs attract each other' or ' they distract each other less than electron of ...
tara's user avatar
  • 41
4 votes
1 answer
416 views

Spin interaction term for a two-particle system of fermions with a potential that contains spin-spin interaction

Consider a two-particle system consisting of two identical fermions in a potential $$V(\vec{r})\vec{\sigma_{1}}\cdot\vec{\sigma_{2}}$$ where $V(\vec{r})$ is the spatial part of the potential and the ...
TheQuantumMan's user avatar
-3 votes
1 answer
1k views

Identical particles: Why is triplet oxygen more stable than singlet oxygen?

Quoting from Eisberg Resnick Quantum Physics: If we consider space variables of two electrons (identical particles) to have almost the same values, then their wavefunctions are 'almost' identical ...
Prasad Mani's user avatar
4 votes
0 answers
362 views

Relative energies of singlet and triplet states in Jablonski diagrams

In a Jablonski diagram, we have singlet and triplet excited states where spin is conserved or changed, respectively. My book says any singlet excited state is found to have higher energy than the ...
Ka Sikh's user avatar
  • 145
-1 votes
1 answer
278 views

Ionization and exchange energy [closed]

As we all know that 'Nitrogen' has higher 'Ionization Energy' than its neighboring elements both carbon and oxygen, opposite to the trend of increasing ionization energy across a period. The reason ...
Govind Prajapat's user avatar