Atomic, Molecular and Optical Physics

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Atomic, Molecular and Optical Physics
Laser and Accelerator Based Studies of Ions,
Atoms and Simple Molecules for the Better
Understanding of Astrophysical Spectra R.L.
Brooks
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Accelerator based Studies

• Cryogenic films of astrophysical interest, such
  as CO, carbon monoxide, can be irradiated with a
  3 MV proton accelerator and the reaction products
  studied spectroscopically.

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• Two different spectrometers, one a grating
  instrument and one an FTIR, can be used to study
  absorption and emission from the UV to the near
  IR and everything in-between.

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• Gas mixtures are sprayed onto a sapphire
  substrate held at 5 K. The thin film of frozen
  material is irradiated with protons and studied
  spectroscopically.

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Cavity ring-down Spectroscopy

• One extremely sensitive, and fairly new
  spectroscopic tool is CRDS, a way to measure
  faint absorption in gases by measuring the
  lifetime of the laser light that escapes from a
  high finesse cavity.

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• A newer application of CRDS is to measure
  absorption in a discharge in which the absorbing
  level is electronically excited. The interesting
  and novel feature is that transitions never
  before observed can be studied.

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• The three transitions labelled with arrows in
  atomic helium have been studied in our
  laboratory. Two of them have never before been
  observed and a measure of the transition
  probability for the singlet-triplet transition
  has been obtained.

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Rare earth doped Laser Crystals

• Studies of Nd3 doped YLF have been undertaken
  using femto-second lasers at McMaster
  Univer-sity. Pump-probe experiments of the
  excited state manifold are ongoing.

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Block diagram of the lasers being used and a
schematic of the pump-probe setup.
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Canadian Light Source
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• Future opportunities for work at the ultra high
  resolution, far infrared beam line at the
  Canadian Light Source in Saskatoon should become
  available. The CLS is a multi-beam line
  synchrotron with one beam line specifically
  designed for far infrared work. One of the
  highest resolution FTIR spectrometers in the
  world will be associated with this beam line to
  perform studies on molecules of astrophysical
  interest.