Finding the color of crystal violet theoretically
$begingroup$
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 9 hours ago
Neil ChowdhuryNeil Chowdhury
1666
$endgroup$
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 9 hours ago
Neil ChowdhuryNeil Chowdhury
1666
$endgroup$
3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
9 hours ago
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
9 hours ago
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
5 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
1 hour 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 9 hours ago
Neil ChowdhuryNeil Chowdhury
1666
$endgroup$
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 9 hours ago
Neil ChowdhuryNeil Chowdhury
1666
asked 9 hours ago
Neil ChowdhuryNeil Chowdhury
1666
asked 9 hours ago
Neil ChowdhuryNeil Chowdhury
1666
asked 9 hours ago
Neil ChowdhuryNeil Chowdhury
1666
asked 9 hours ago
Neil ChowdhuryNeil Chowdhury
1666
1666
3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
9 hours ago
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
9 hours ago
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
5 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
1 hour ago
add a comment |
3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
9 hours ago
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
9 hours ago
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
5 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
1 hour ago
3
3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
9 hours ago
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
9 hours ago
2
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
9 hours ago
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
9 hours ago
1
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
5 hours ago
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
5 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
1 hour ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
1 hour ago
add a comment |
1 Answer
1
active
oldest
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 8 hours ago
PJ RPJ R
997113
$endgroup$
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
7 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
5 hours ago
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "431"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fchemistry.stackexchange.com%2fquestions%2f109670%2ffinding-the-color-of-crystal-violet-theoretically%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
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 8 hours ago
PJ RPJ R
997113
$endgroup$
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
7 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
5 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 8 hours ago
PJ RPJ R
997113
$endgroup$
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
7 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
5 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 8 hours ago
PJ RPJ R
997113
$endgroup$
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 8 hours ago
PJ RPJ R
997113
edited 7 hours ago
answered 8 hours ago
PJ RPJ R
997113
answered 8 hours ago
PJ RPJ R
997113
answered 8 hours ago
PJ RPJ R
997113
997113
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
7 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
5 hours ago
add a comment |
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
7 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
5 hours ago
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
7 hours ago
$begingroup$
Here's about limitations of pinging chemistry.meta.stackexchange.com/questions/3889/…
$endgroup$
– Mithoron
7 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
5 hours ago
$begingroup$
"... don't see what additional physical insight ..." Word.
$endgroup$
– Karl
5 hours ago
add a comment |
Thanks for contributing an answer to Chemistry Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fchemistry.stackexchange.com%2fquestions%2f109670%2ffinding-the-color-of-crystal-violet-theoretically%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
var $window = $(window),
onScroll = function(e) {
var $elem = $('.new-login-left'),
docViewTop = $window.scrollTop(),
docViewBottom = docViewTop + $window.height(),
elemTop = $elem.offset().top,
elemBottom = elemTop + $elem.height();
if ((docViewTop elemBottom)) {
StackExchange.using('gps', function() { StackExchange.gps.track('embedded_signup_form.view', { location: 'question_page' }); });
$window.unbind('scroll', onScroll);
}
};
$window.on('scroll', onScroll);
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
3
$begingroup$
You need something more sophisticated than particle in a box, probably (at least) Huckel theory.
$endgroup$
– orthocresol♦
9 hours ago
2
$begingroup$
Using some decent software.
$endgroup$
– Mithoron
9 hours ago
1
$begingroup$
You would have to make ridiculous simplifications. For starters, this molecule is not perfectly planar.
$endgroup$
– Karl
5 hours ago
$begingroup$
@karl it isn't planar? What happens?
$endgroup$
– Oscar Lanzi
1 hour ago