G8316_StudentQuestions: Lecture 4
(1)
From Shipra (U Miami)
Question No. 1: Slide No. 19
Fig (b) shows that at zero magnetic field, transition from triplet to singlet state and
vice-versa is possible.
Fig (c) shows that transition from only T0 to S and vice-versa is possible.
So, in both the cases, ISC is allowed. The only difference is that in second case the
rate of ISC will depend upon the population of T0 state.
Have I understood this correctly?
Question No. 2: Slide No. 38
In CIDNP, are we basically trying to excessively populate one of the energy states
(Higher or Lower) by absorbing/emitting light, so as to see a better NMR signal?
(2)
From Shampa (U Miami)
I have few questions regarding Lecture 4on iclass. I could not understand 'the effect
of external magnetic field on the cage effect' that you have discussed in page 26-27
of 'G8316_Lecture4_Spin.pdf'.
In page 26 the sentence 'Magnetic field causes 8.81b to increase in the competition.
Therefore, cage effect decreases (more exit from host cage)' is not very clear to me.
If you can please explain me this point once more I will be thankful to you.
(3)
From Rajib (U Miami)
I have a query on the mechanism of crossing from T to S (slide #16). My question,
Is the mechanism of spin rephasing and spin flipping comparable to T1 and T2
relaxation mechanism in NMR?
(4)
From Elamparuthi (U Miami)
Could you explain why triplets couple to nuclei with spin will cross to the singlets
faster than triplets coupled to nuclei withouth spins?