Atomic, Molecular and Optical Physics

Laser and Accelerator Based Studies of Ions, Atoms and Simple Molecules for theBetter Understanding of Astrophysical Spectra

R.L. Brooks

Accelerator based StudiesAccelerator based Studies

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

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

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

Cavity ring-down SpectroscopyCavity ring-down Spectroscopy

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

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

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

Rare earth doped Laser CrystalsRare earth doped Laser Crystals

Studies of NdStudies of Nd3+3+ doped doped YLF have been YLF have been undertaken using undertaken using femto-second lasers femto-second lasers at McMaster Univer-at McMaster Univer-sity. Pump-probe sity. Pump-probe experiments of the experiments of the excited state manifold excited state manifold are ongoing.are ongoing.

Block diagram of the lasers being used and a Block diagram of the lasers being used and a schematic of the pump-probe setup.schematic of the pump-probe setup.

Canadian Light SourceCanadian Light Source

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