Observation of the Infrared Spectra of the Deuterated Triatomic Hydrogen Molecular Ions: H(2)D(+), HD(2)(+), and D(3)(+)
The infrared vibrational-rotational spectra of the deuterated triatomic hydrogen molecular ions, H(,2)D('+), HD(,2)('+), and D(,3)('+) have been observed with the Doppler -tuned ion-beam laser spectroscopic method with collision detection. Triatomic hydrogen molecular ions are produced in a coaxial electron-impact ion source. Next, the ions are accelerated and formed into a beam of several keV energy, which is then intercepted at a small angle by a frequency -stabilized CO laser beam. The energy of the ion beam is adjusted to Doppler-shift an ion transition into resonance with a nearby laser line. On resonance, the laser light stimulates the transition to take place. If the resonating states differ in population, the laser-induced transition produces a net population transfer. The occurrence of population transfer is detected by monitoring the transmission of the ion beam through a gas target after laser interaction. The transmission through the target is dependent upon the ion beam population distribution and, therefore, the laser -induced transition can be detected by detecting the change of the transmission of the ion beam. A mass analyzer before the target gas facilitates the mass identification of the observed transition. We have measured 45 D(,3)('+) transition frequencies, 9 H(,2)D('+) transition frequencies, and 31 HD(,2)('+) transition frequencies, all between 1650 and 2000 cm(' -1), to better than 0.0005 cm('-1) or 0.3 ppm. The identifications of the quantum numbers are still in progress. This study should greatly help the search of H(,3)('+) and H(,2)D('+) ions in interstellar medium.
- Pub Date:
- Physics: Molecular