CHM 411/511
Problem Set 2
1. List and describe the basic components of all spectrometers.
2. Calculate the frequency in hertz, the wave number, the energy in joules, and the energy in kJ/mol
associated with the 5.715 μm vibrational absorption band of an aliphatic ketone.
3. What light sources are suitable as continuum sources of UV and VIS light? What light sources are
suitable as continuum sources for near IR and IR light?
4. Suggest instrument components and materials for constructing an instrument that would be well suited
for each of the following purposes:
a) The investigation of the fine structure of absorption bands in the region of 450 to 750 nm.
b) Obtaining absorption spectra in the far infrared (20 to 50 μm).
c) Determining the wavelengths of flame emission lines for metallic elements in the region from 200 to
780 nm.
5. Contrast spontaneous and stimulated emission.
6. Briefly explain the advantage of using an eximer laser.
7. Sketch the transmission curve (T versusλ) for a low pass optical filter with a cutoff wavelength of 450
nm. What color would the filter be?
8. An interference filter is constructed with an MgF2 dielectric (index of refraction= 1.36). What are the
first, second, and third order wavelengths transmitted by the filter if the dielectric layer is 500 nm thick?
9. Generally, a single grating can be used for a monochromator that operates in the UV/VIS domain.
However, a monochromator operating in the IR domain usually has 2 gratings and switches them at
about 200 cm-1. Why?
10. Briefly explain how the photoelectric effect yields a signal in a vacuum phototube. Include in your
explanation why a vacuum phototube or photomultiplier tube is blind to IR light.