All Questions
Tagged with symmetry physical-chemistry
26
questions
6
votes
2
answers
364
views
Potential wells and symmetry in absorption spectroscopy
In a course I am following, we are analyzing the potential wells in molecular absorption spectroscopy.
For molecules with more than one normal mode, we can study the potential wells involved in ...
- 163
8
votes
1
answer
3k
views
Determination of +/- reflections in sigma molecular term symbols
This page, which depicts the molecular term symbols for the $\ce{O2}$ and $\ce{O2-}$ (Edit: Mistaken on $\ce{O2-}$) molecules, perhaps best summarizes the full scope of my questions. In general, I don'...
- 1,648
13
votes
2
answers
2k
views
Rule of mutual exclusion: is the converse true?
There is a "famous" rule in spectroscopy,1 that goes this way:
If a compound is centrosymmetric, then its normal vibrational modes cannot be simultaneously IR and Raman active.
and this is simple ...
- 71.6k
3
votes
0
answers
3k
views
How to tell if a vibrational mode in benzene is IR and/or Raman active?
Consider the vibrational mode that corresponds to the boat-like bending of a benzene ring. Is it (i) Infrared active? (ii) Raman active?
This question was asked in an assignment in my college. ...
- 49
3
votes
2
answers
1k
views
Are there different types of symmetry? [duplicate]
What factor does the symmetry of a molecule play?
For example, I know water is asymmetric so does this therefore make water polar (I know in fact that is is)? It may sound ignorant due to my lack of ...
- 435
2
votes
1
answer
552
views
Find moment of inertia around two axes of sulphur dioxide
Problem:
Find the moment of inertia for 2 axes of $\ce{SO2}$. The rotational constants are given in $\pu{MHz}$. The answer is required to be $10^{-46}\rm~ kg\cdot m^2$, 7 digit accuracy.
I ...
- 29
1
vote
0
answers
150
views
Structure and Vibrational Spectroscopy
What are the irreducible representations of the C-O stretching modes in free CO, $\ce{[Fe(CO)5][Fe(CO)4]^2-}$?
I think Free CO irreducible representation is A2.
For $\ce{[Fe(CO)5]}$ irreducible ...
- 11
5
votes
0
answers
185
views
Analysis of metal carbonyl bonding in Fe(CO)5 using molecular orbitals
I am really struggling with this question we have been set in class:
Metal-carbonyl bonding: Conceptionally, one can build up $\ce{[Fe(CO)5]}$ from the $\ce{Fe(CO)4}$ fragment plus free $\ce{CO}$ in ...
- 51
1
vote
0
answers
211
views
Creating Molecular Orbital and Walsh Diagrams
Does anyone know of a good website to create your own MO and Walsh diagrams? Could you potentially make them on a software package such as excel?
Any advice on this would be greatly appreciated.
- 11
2
votes
2
answers
5k
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Symmetry representations for acetonitrile (CH3CN)
Can anybody share the symmetry labels for acetonitrile ($\ce{CH3CN}$), please?
I mean to assign the symmetry labels to orbitals of acetonitrile
34
votes
1
answer
10k
views
When is it true that more nodes equals higher energy?
Consider all the MOs of some isolated molecule. (It could be a single
atom too; I'll use MO to refer to AOs as well.) Number them in
increasing order of the number of nodes (node = surface where the ...
- 2,757