# Homework Help: Fluorescence Spectroscopy Q?

1. Sep 22, 2010

### tbedford

1. The problem statement, all variables and given/known data

calculate the angle between the absorption dipole and the emission dipole of specific blue maleimide ?

limiting polarization was determined to be 0.5 and anisotropy 0.4

Relevant equations

I know from lectures that the angle should in fact be zero because the actual max of limiting polarization is 0.5, but I don't know how to work the formula to get to this answer. (if the limiting polarisation was not 0.5 I don’t think I could find the angle)

The attempt at a solution

formula 1/po - 1/3 = 5/3(2 / 3cos2 ɸ -1)
where po is the limiting polarization (0.5)

2. the problem statement, all variables and given/known data

if we add actin (42KDa) to the solution which will bind profiling (14KDa), estimate the anisotropy of the complex?

Partial specific volume v= 0.74
Degree of hydration hy= 0.3g of water per g of protein
Universal gas constant R= 8.13x107
absolute temperature T= 293 ̊c
Viscosity of the medium η= 0.01 dynes.s/cm2
Life time t= 3.32ns

The attempt at a solution

Using tc = ηM(ν + hy)/RT

= 0.01 x 56kda x (0.74 + 0.3) / 8.13x107 x 293
= 5.106x10-12 s
= 5.106x10-3 ns

Then use ro/r = (1+ t/tc)
= 1+ 3.23/5.106x10-3 ns
= 632.59 ?

I don’t know if any of this is right firstly and then if it is how do I get the anisotropy from it because I don’t know the limiting anisotropy?

Last edited: Sep 22, 2010