High-resolution molecular spectroscopy using laser and synchrotron radiation

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The different wavelengths of light emitted or absorbed by molecules - the molecular spectrum - encodes a wealth of information about the internal structure and the physics inherent to the species being observed. Each molecule's spectrum is unique, and can be used like a fingerprint to identify it. This property is powerful, especially so in astrophysics, since the only information we receive from remote stars, galaxies, and the interstellar medium comes from the light they produce or absorb.******This proposal describes a program of research that records molecular spectra of species that have known or potential relevance to astrophsyics. Many of the molecules we study are quite unstable because they react with atmospheric gases and are quickly destroyed - but in space, where the density of matter is low, they persist for long times. We create these unstable molecules by stripping material from a rod housed in a vacuum chamber with a laser pulse. The hot plume of material then reacts with a fast-moving jet of helium gas entrained with stable reactant molecules like methane or methanol to produce the unstable species found in space. The jet is crossed with laser beams whose wavelengths can be continuously varied, and when the wavelength matches that of an absorption the molecule fluoresces, producing a signal that we can detect to map the spectrum. We specialize in molecules containing an atom of metal that comes from the rod, and is bonded to a ligand that comes from the reactant gas. Metal-bearing molecules like FeH and CrH; FeO, VO and TiO; and MgNC and MgCN have already been observed in the atmospheres of stars (including our sun). We will look for species like FeP, VP, and TiP which one day may be observed in space.******The construction of the Canadian Light Source synchrotron in Saskatoon, SK has added an exciting new possibility for molecular spectroscopy experiments - access to intense and well-collimated light at very long wavelengths. The synchrotron light allows us to rapidly acquire spectra of extremely high quality in the difficult 2-30 terahertz region of the electromagnetic spectrum, where the fundamental vibrations of many larger molecules of astrophysical interest lie. Many currently-active satellite-borne instruments are sensitive to this region, and the data my students and I collect provides a valuable database for comparison with the spectra these satellites collect from the universe around us.