7
votes
To what extent can coarse-grained models retain the essential quantum mechanical characteristics of a system?
Generally, in multi-scale modelling, QM characteristics are irrelevant. Most of the processes that we study for these multi-scale modelling are thermodynamics driven. So, I will be very surprised if ...
6
votes
Why is electron correlation called the "chemical glue"?
Coincidentially, I recently read Perdew's recent autobiographical article where he also mentions the concept of "chemical glue." His simple image is as follows:
The exchange–correlation ...
5
votes
Is the electron-electron interaction to blame, for the added complexity of using "orbitals" for an N-electron system?
Interpreting the question
For a 1-electron system, wavefunctions and orbitals are the same thing. For a 2-electron system, or any N-electron system with N>1, we can use "orbitals" to ...
4
votes
Accepted
Is the one-electron reduced density matrix enough in DFT?
tl;dr
"Well yes, but actually no."
— the Pirate Captain (paraphrased), The Pirates! In an Adventure with Scientists!
The universal 2RDM functional is known (and linear!), but 2RDMs are ...
3
votes
Why is electron correlation called the "chemical glue"?
Normally the correlation energy is defined to be:
$E_{corr}^{basis} = E_{FCI}^{basis} - E_{HF}^{basis}$
where the superscript basis denotes each calculated in a fixed basis set. The correlation energy ...
3
votes
Accepted
How is the LUMO lower energy than the HOMO for triplet state restricted-open shell DFT calculation?
It would be better to use the word SOMO (Singly Occupied Molecular Orbital), not HOMO. Now assume that you have two SOMOs (or SOMO and SOMO-1 if you prefer). Here are my suggestions:
The first thing ...
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