Finding the color of crystal violet theoretically
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I am trying to find the color of an organic molecule, crystal violet, theoretically. 
I suspect that the color is due to the large conjugated system. My question is, how would I go about finding the energy levels of such a system? I know how to solve the Schrodinger equation for a particle in a ring or a box (i.e. benzene, or a poly-diene) to solve for energy levels and find the lowest-wavelength transition. But how would I do it for this sort of molecule?
quantum-chemistry
asked 11 hours ago
Neil ChowdhuryNeil Chowdhury
1716
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add a comment |
$begingroup$
I am trying to find the color of an organic molecule, crystal violet, theoretically.
I suspect that the color is due to the large conjugated system. My question is, how would I go about finding the energy levels of such a system? I know how to solve the Schrodinger equation for a particle in a ring or a box (i.e. benzene, or a poly-diene) to solve for energy levels and find the lowest-wavelength transition. But how would I do it for this sort of molecule?
quantum-chemistry
asked 11 hours ago
Neil ChowdhuryNeil Chowdhury
1716
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3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
11 hours ago
2
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Using some decent software.
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– Mithoron
10 hours ago
1
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You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
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– Karl
7 hours ago
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@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
2 hours ago
add a comment |
$begingroup$
I am trying to find the color of an organic molecule, crystal violet, theoretically.
I suspect that the color is due to the large conjugated system. My question is, how would I go about finding the energy levels of such a system? I know how to solve the Schrodinger equation for a particle in a ring or a box (i.e. benzene, or a poly-diene) to solve for energy levels and find the lowest-wavelength transition. But how would I do it for this sort of molecule?
quantum-chemistry
asked 11 hours ago
Neil ChowdhuryNeil Chowdhury
1716
$endgroup$
I am trying to find the color of an organic molecule, crystal violet, theoretically.
I suspect that the color is due to the large conjugated system. My question is, how would I go about finding the energy levels of such a system? I know how to solve the Schrodinger equation for a particle in a ring or a box (i.e. benzene, or a poly-diene) to solve for energy levels and find the lowest-wavelength transition. But how would I do it for this sort of molecule?
quantum-chemistry
quantum-chemistry
asked 11 hours ago
Neil ChowdhuryNeil Chowdhury
1716
asked 11 hours ago
Neil ChowdhuryNeil Chowdhury
1716
asked 11 hours ago
Neil ChowdhuryNeil Chowdhury
1716
asked 11 hours ago
Neil ChowdhuryNeil Chowdhury
1716
asked 11 hours ago
Neil ChowdhuryNeil Chowdhury
1716
1716
3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
11 hours ago
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
10 hours ago
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
7 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
2 hours ago
add a comment |
3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
11 hours ago
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
10 hours ago
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
7 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
2 hours ago
3
3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
11 hours ago
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
11 hours ago
2
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
10 hours ago
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
10 hours ago
1
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
7 hours ago
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
7 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
2 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
2 hours ago
add a comment |
1 Answer
1
active
oldest
votes
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For a reliable and experimentally comparable answer, you really need to use a numerical method rather than a pencil and paper estimation. For an organic system this size you'll probably be safe using time-dependent density functional theory (TDDFT). Most computational chemistry packages have this built in. Off the top of my head, I know that Gaussian (commercial–standard for organic molecules like this), and GAMESS (free) both have TDDFT built in.
If you're intent on using a toy method you could use Hückel theory as orthocresol suggested. You could in principle tune the parameters of such a model until the excitation energy matches the experimental result, but I don't see what additional physical insight this would give you.
answered 10 hours ago
PJ RPJ R
1,007113
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$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
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– Mithoron
8 hours ago
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"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
7 hours ago
add a comment |
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1 Answer
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active
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1 Answer
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active
oldest
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active
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votes
$begingroup$
For a reliable and experimentally comparable answer, you really need to use a numerical method rather than a pencil and paper estimation. For an organic system this size you'll probably be safe using time-dependent density functional theory (TDDFT). Most computational chemistry packages have this built in. Off the top of my head, I know that Gaussian (commercial–standard for organic molecules like this), and GAMESS (free) both have TDDFT built in.
If you're intent on using a toy method you could use Hückel theory as orthocresol suggested. You could in principle tune the parameters of such a model until the excitation energy matches the experimental result, but I don't see what additional physical insight this would give you.
answered 10 hours ago
PJ RPJ R
1,007113
$endgroup$
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
8 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
7 hours ago
add a comment |
$begingroup$
For a reliable and experimentally comparable answer, you really need to use a numerical method rather than a pencil and paper estimation. For an organic system this size you'll probably be safe using time-dependent density functional theory (TDDFT). Most computational chemistry packages have this built in. Off the top of my head, I know that Gaussian (commercial–standard for organic molecules like this), and GAMESS (free) both have TDDFT built in.
If you're intent on using a toy method you could use Hückel theory as orthocresol suggested. You could in principle tune the parameters of such a model until the excitation energy matches the experimental result, but I don't see what additional physical insight this would give you.
answered 10 hours ago
PJ RPJ R
1,007113
$endgroup$
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
8 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
7 hours ago
add a comment |
$begingroup$
For a reliable and experimentally comparable answer, you really need to use a numerical method rather than a pencil and paper estimation. For an organic system this size you'll probably be safe using time-dependent density functional theory (TDDFT). Most computational chemistry packages have this built in. Off the top of my head, I know that Gaussian (commercial–standard for organic molecules like this), and GAMESS (free) both have TDDFT built in.
If you're intent on using a toy method you could use Hückel theory as orthocresol suggested. You could in principle tune the parameters of such a model until the excitation energy matches the experimental result, but I don't see what additional physical insight this would give you.
answered 10 hours ago
PJ RPJ R
1,007113
$endgroup$
For a reliable and experimentally comparable answer, you really need to use a numerical method rather than a pencil and paper estimation. For an organic system this size you'll probably be safe using time-dependent density functional theory (TDDFT). Most computational chemistry packages have this built in. Off the top of my head, I know that Gaussian (commercial–standard for organic molecules like this), and GAMESS (free) both have TDDFT built in.
If you're intent on using a toy method you could use Hückel theory as orthocresol suggested. You could in principle tune the parameters of such a model until the excitation energy matches the experimental result, but I don't see what additional physical insight this would give you.
answered 10 hours ago
PJ RPJ R
1,007113
edited 8 hours ago
answered 10 hours ago
PJ RPJ R
1,007113
answered 10 hours ago
PJ RPJ R
1,007113
answered 10 hours ago
PJ RPJ R
1,007113
1,007113
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
8 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
7 hours ago
add a comment |
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
8 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
7 hours ago
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
8 hours ago
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
8 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
7 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
7 hours ago
add a comment |
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3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
11 hours ago
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
10 hours ago
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
7 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
2 hours ago