You are Here: Home

# Quantum mechanic

Announcements Posted on
Four hours left to win £100 of Amazon vouchers!! Don't miss out! Take our short survey to enter 24-10-2016
1. The allowed energy levels (En) for a particle of mass m in a one-dimensional box of length a are given by: En = n2h2/(8ma2) , n = 1, 2, 3, ... The carbocyanine dye 1 has 10 electrons in the conjugated π-system (highlighted in bold). The energy levels (“orbital energies”) of the π-electrons can be estimated by treating the πsystem as a one-dimensional box of length 1.40 nm. Each level can then be occupied by up to 2 electrons. 1 Calculate the energy difference between 5th and 6th energy levels (i.e., the gap between the highest occupied and lowest unoccupied orbitals). Convert this energy to a wavelength, λ. The actual absorption wavelength is 575 nm. Comment on why the result of your calculation is different from this. h = 6.626 × 10–34 J s, me = 9.109 × 10–31 kg, c = 2.997 × 108 m s–1
2. (Original post by Rose86)
The allowed energy levels (En) for a particle of mass m in a one-dimensional box of length a are given by: En = n2h2/(8ma2) , n = 1, 2, 3, ... The carbocyanine dye 1 has 10 electrons in the conjugated π-system (highlighted in bold). The energy levels (“orbital energies”) of the π-electrons can be estimated by treating the πsystem as a one-dimensional box of length 1.40 nm. Each level can then be occupied by up to 2 electrons. 1 Calculate the energy difference between 5th and 6th energy levels (i.e., the gap between the highest occupied and lowest unoccupied orbitals). Convert this energy to a wavelength, λ. The actual absorption wavelength is 575 nm. Comment on why the result of your calculation is different from this. h = 6.626 × 10–34 J s, me = 9.109 × 10–31 kg, c = 2.997 × 108 m s–1
Here's just a quick bit of working out on this one (hopefully the attachments work)

The reason the wavelength aren't identical is because the particle in a box is a very simplified model and so it can't be expected to completely agree with the reality of the situation, given that fact, the agreement you get is quite good
Attached Images

3. (Original post by MexicanKeith)
Here's just a quick bit of working out on this one (hopefully the attachments work)

The reason the wavelength aren't identical is because the particle in a box is a very simplified model and so it can't be expected to completely agree with the reality of the situation, given that fact, the agreement you get is quite good
Thank You, but it was few days ago and I have already done it
4. (Original post by Rose86)
Thank You, but it was few days ago and I have already done it
Ahh well, never mind
5. (Original post by MexicanKeith)
Ahh well, never mind
Anyway Thank you😘

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: October 11, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Who is getting a uni offer this half term?

Find out which unis are hot off the mark here

### How to get a 1st class degree

Poll
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.