CHM317, HW2 page 1 of 3.
CHM317 Homework assignment #2
Due on Monday, February 13, 2011 at the beginning of lecture.
Show your work. Full credit may not be awarded unless the work is shown.
A total of 38 marks are available.
1. Fluorescence
(4 marks)
Structures, emission spectra, fluorescence lifetimes (
) and quantum yields (called Q
here) for eosin and erythrosine B (ErB) are shown in the Figure below.
(a) Calculate the radiative rate constant for Eosin and ErB.
(b) Calculate the sum of all nonradiative rate constants for Eosin and ErB.
(c)
What rate(s) account for the lower quantum yield of ErB compared to Eosin?
Picture from J.R. Lakowicz,
Principles of Fluorescence Spectroscopy
, 3
rd
edition.
2. Diffraction of Light
(8 marks)
You are working with a monochromator of focal length 0.500 meters that sends light into
a grating (1200 lines/mm) at an incidence angle of 35º.
(a) At what angles are the first order diffraction lines of red (650 nm), green (530 nm)
and blue (450 nm)? At what angles do the second order diffraction lines appear for each
of these wavelengths?
(b) Sketch the incoming and outgoing 650 nm, 530 nm and 450 nm light at the grating.
Label all relevant angles.
(c) What wavelength of light has 2
nd
order diffraction at the same angle as the 1
st
order
diffraction of 530 nm light? What could be done to ensure that none of this unwanted 2
nd
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 Spring '11
 Jokusch
 Photon, Wavelength, nm light, Principles of Fluorescence Spectroscopy

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