Photoionization and photoelectron spectroscopy of molecular Rydberg states

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5180077

Miller, P J

Spectroscopic investigations of molecular Rydberg states have been carried out using both one- and multi-photon laser techniques. Third-harmonic generation of tunable vacuum ultraviolet (VUV) radiation has been employed to obtain high resolution one-photon ionization spectra of NO and NH{sub 3}. The NO results have yielded autoionization linewidths that can be compared to multichannel quantum defect theory calculations. In NH{sub 3}, autoionizing Rydberg states have been seen converging to the v{sub 2}{sup +} = 3 and 5 levels of the ion. Photoelectron spectroscopy of these levels confirms a propensity for {Delta}v = {minus}1 vibrational autoionization. In another application of coherent VUV light, photolysis of CH{sub 4} at 118.3 nm coupled with mass spectroscopy has given a direct measurement of the relative photofragment yields. The use of (2 + 1) multiphoton ionization-photoelectron spectroscopy (MPI-PES) in conjunction with a magnetic-bottle photoelectron spectrometer has revealed the {nu}{sub 1} + n{nu}{sub 2} combination band of the NH{sub 3} {tilde C}{prime} state. (3 + 1) MPI-PES of 0{sub 2} has confirmed the presence of strong Rydberg-valence state mixing in the E {sup 3}{Sigma}{sub u}{sup {minus}} state, as had been theoretically predicted. Finally, (2 + 1) MPI-PES studies of O{sub 2} C {sup 3}{Pi}{sub g}, (v{prime} = 0 - 3) levels has shown the presence of a shape resonance at the ionization threshold.

• Research Organization: Yale Univ., New Haven, CT (United States)
• OSTI ID: 5180077
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
AMMONIA
CHALCOGENIDES
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ENERGY LEVELS
EXCITED STATES
FAR ULTRAVIOLET RADIATION
HYDRIDES
HYDROGEN COMPOUNDS
IONIZATION
MULTI-PHOTON PROCESSES
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
PHOTOIONIZATION
RADIATIONS
RESONANCE
RYDBERG STATES
SPECTRA
SPECTROSCOPY
ULTRAVIOLET RADIATION