Gas-Phase Terahertz Spectroscopy and the Study of Complex Interstellar Chemistry

摘要: Terahertz spectroscopy holds great promise in the advancement of field astrochemistry. The sensitive observation interstellar THz radiation is expected to lower detection limits and allow study larger more complex species than currently possible at millimeter wavelengths, which will place further constraints on chemical models permit a direct comparison organic compounds seen carbonaceous chondrites. With successful recent launch Herschel Space Telescope, give high-fidelity access for first time, completion Atacama Large Millimeter Array (ALMA) by 2013, astronomy era upon us. Unfortunately, laboratory presents significant challenges be soon lagging behind newly available observational platforms. Technologies extend capabilities high-resolution spectroscopic systems into domain are actively being pursued many fronts, but affordable that broadly tunable, achieve necessary resolution not yet available. work this thesis should therefore as part effort transition from centimeter-/millimeter-wave taking astrochemistry community. As thesis, searches organics hydroxyacetone (CH₃COCH₂OH), 2-cyanoethanol (OHCH₂CH₂CN) methoxyacetonitrile (CH₃OCH₂CN) were attempted wavelengths. unsuccessful nature these highlight current studying chemistry using pure rotational spectroscopy. characterization spectra molecules nonetheless important it aid assignment description substructure band shapes their torsional spectra, features may detection; methods such rapidly efficiently collected fit automated spectrometers modern software tools. spectrum furthermore interest due presence very low barrier internal rotation molecule. Many compounds, both known potential future targets, have functional groups capable structure; so understanding effects rotor case benefit general understand rotation. In searching new molecules, wavelengths higher frequencies, complete importance substraction contribution spectra. ground-state methanol, most "interstellar weed", catalogued described detail through region accessible with ALMA. Lastly, increase sensitivity spectrometers, use Fabry-Perot cavities frequencies explored. Such resonant hold significantly path lengths system novel techniques. Optimal configurations achievable Q-factors discussed, extensions Fourier Transform MicroWave (FT-MW) techniques frequencies.