/ital l/- and /ital n/-changing collisions during interaction of a pulsed beam of Li Rydberg atoms with CO/sub 2/
The pulsed Li atomic beam produced in our experiment is based on controlledtransversely-excited-atmospheric CO/sub 2/ laser--inducedablation of a Li metal target. The atomic beam is propagated in vacuum or inCO/sub 2/ gas at low pressure. Atoms in the beam are probed bylaser-induced fluorescence spectroscopy. This allows the determination oftime-of-flight and velocity distributions. Li Rydberg states(/ital n/=5--13) are populated in the beam by two-step pulsed-laserexcitation. The excited atoms interact with CO/sub 2/ molecules./ital l/- and /ital n/-changing cross sections are deduced from the timeevolution of the resonant or collision-induced fluorescence following thisselective excitation. /ital l/-changing cross sections of the order of10/sup 4/ A/sup 2/ are measured; they increasewith /ital n/ as opposed to the plateau observed for Li/sup */ collidingwith a diatomic molecule. This behavior is qualitatively well explained in theframework of the free-electron model. /ital n//r arrow//ital n/' changing processes withlarge cross sections (10--100 A/sup 2/) are alsoobserved even in the case of large electronic energy change(..delta../ital E//sub /ital nn/'//gt/10/sup 3/ cm/sup /minus/1/). These resultscan be interpreted in terms of resonant-electronic to vibrational energytransfers between Li Rydberg states and CO/sub 2/ vibrational modes.
- Research Organization:
- Groupe de Recherche sur l'Energetique des Milieux Ionises, Universite d'Orleans, Boiat/Bte Postale No. 6759, 45067 Orleans CEDEX 2, France(FR)
- OSTI ID:
- 6061561
- Journal Information:
- Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 40:1; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ABLATION
ALKALI METALS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
ATOMIC BEAMS
BEAMS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FLUORESCENCE
IRRADIATION
LASER RADIATION
LITHIUM
LUMINESCENCE
METALS
MOLECULE COLLISIONS
OXIDES
OXYGEN COMPOUNDS
PULSED IRRADIATION
RADIATIONS
RYDBERG STATES