Observation of the infrared spectrum of the helium hydride molecular ion

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1980

OSTI ID:5281003

Tolliver, D E

This dissertation describes the first high-precision observation of the infrared spectrum of the helium hydride molecular ion HeH/sup +/. The frequencies of five vibrational-rotational transitions in the range 1700 to 1900 cm/sup -1/ in the X/sup 1/..sigma../sup +/ ground electronic state of /sup 4/HeH/sup +/ have been measured to +-0.002 cm/sup -1/(+-1 ppM). The Doppler tuned ion beam laser spectroscopic method was used in making the measurements: In a region of constant electrostatic potential, an HeH/sup +/ ion beam of several keV energy is intercepted at a small angle by a beam from a carbon monoxide infrared gas laser. 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 transitions to take place. If the resonating states differ in population, the laser-induced transitions produce a net population transfer. The occurrence of population transfer is detected by monitoring the transmission of the ion beam through a gas target downstream from the laser beam interaction region. The transmission through the target is dependent upon the ion beam vibrational-state population distribution and therefore is sensitive to changes in the population distribution, because the cross-section for charge-exchange neutralization of an incident ion is dependent upon the vibrational state of the ion.The current interest in molecular ions in general, and in HeH/sup +/ in particular, is explained. The existing theory of the structure of HeH/sup +/ is summarized and a comprehensive listing of theoretical treatments of the structure of HeH/sup +/ is given. The meager previous experimental work on HeH/sup +/ is reviewed. The principles of the Doppler tuned ion beam laser resonance method are discussed and the experimental apparatus used is described in detail.

• Research Organization: Arizona Univ., Tucson (USA)
• OSTI ID: 5281003
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
BEAMS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHARGE EXCHANGE
CHARGED PARTICLES
DOPPLER EFFECT
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FREQUENCY MEASUREMENT
HELIUM COMPOUNDS
HELIUM HYDRIDES
HYDRIDES
HYDROGEN COMPOUNDS
INFRARED SPECTRA
ION BEAMS
IONS
LASER SPECTROSCOPY
MOLECULAR IONS
MOLECULAR STRUCTURE
OXIDES
OXYGEN COMPOUNDS
RARE GAS COMPOUNDS
RESONANCE
SPECTRA
SPECTROSCOPY
VIBRATIONAL STATES